To serve or not to serve, to stock or not to stock – by Supply Chain Detective

If you asked any CEO, Sales Executive or Marketing head what is the customer service level they desire in the organization they’d invariably say 100%. And hearing that answer the Supply Chain VP will invariably shake their heads and flee the room before you could ask them the same question.

But why, you might ask, such an expectation is unreasonable for any organization in any industry? Intuitively, it seems alright to want to sell to anyone who is willing to pay you in crispy greens. In fact, primary purpose of existence of organization is shareholder value creation? Which in simple words mean that organizations solely exist to earn profit by selling their stuff.

Before we delve deep – keep this thought at the back of your mind –

Organizations aim to maximize their profit

Let us try to understand this problem and define our problem statements more clearly.

1.Why it is unreasonable to have customer service level at 100%? And if it is, indeed, unreasonable then,

2.What is the optimum service level?

Qualitative Approach

Let us suppose you are the store manager in the said organization that sells consumer goods. You are responsible for managing stock on the shelves and ordering them before they go out of stock. Customer Service Level is your primary KPI and it is defined as percentage of times customer gets on the shelf whatever he is looking for.

Let us also imagine that one fine morning you get a memo from the CEO, the Sales VP and the marketing head (who must truly hate the supply chain guy) have decided to set this Customer Service Level as 100% as the new target.

Just yesterday you had to turn a guy back who wanted to buy five dozen television sets. With this new policy you’d have to stock everything that the next customer might need.

Oh heck, you realize that you need to stock your party supplies section for the next customer who accidentally invited 21,000 guests on her birthday. Even though the probability of this happening is very small, it is not zero. And the customer service target of 100% nudges you to be stocked for this small probability. Even if this means tons of overstocking and surely lot of wastage later, you have to be ready for all the extreme cases of demand.

You let out a muffled scream and consider quitting your job before sending a polite reply to your boss asking for permission to stock infinite inventory.

Quantitative Approach

We now intuitively understand why the customer service level can not be 100%. It would mean keeping infinite inventory for any possible customer demand that may or may not come. Keeping high inventory is almost sure to lead to excess inventory and write-offs ultimately making it a loss making proposition. But how much then should we “serve” before it starts becoming a loss making proposition.

Let us first take an example to understand the underlying logic before we go on to make complex models.

Imagine that you are that poor store manager responsible for customer service as well as inventory cost. The product that you sell costs $8 and you sell it at $20 for a net profit of $12. However, if you are unable to sell it, you’d incur a loss of $8 that was product cost.

The trade-off here is the profit that you’d earn if the customer walks in and you have it in your inventory


The loss that you’d incur if you stock and he doesn’t turn up.

So, should you buy the next unit  of inventory (it is very important to note that we are only talking about a single incremental unit) if there is only 25% chance that you’ll be able to sell it? What if this probability is 50%? 75%?

If the probability is 100%, that is you are sure to sell that next unit (I repeat, only one incremental unit) of product, then it’s a no-brainer that you’d want to stock it for a sure-shot profit of $12.

Now let’s take the next case where there is only 25% chance that you’ll sell it and make a profit of $12 but there is 75% chance that you won’t be able to sell it thereby incurring a loss of $8.

Your expected payoff from this extra inventory is = (25% x $12) + (75% x – $8)

= – $3

Since your expected payoff is negative when the probability is 25% , you’d not want to store this next unit of stock.

Similarly, the payoffs at 50% selling probability (Let’s call it P50 ) is  +$2 and at P75 is +$7

Let us summarize these results:

P25 = – $3

P50 = +$2

P75 = +$7

So, somewhere between 25% and 50% selling probability, keeping that extra unit in inventory became a profit making proposition. With little bit of maths we can find that probability is 40%

So, as long as probability of selling the next unit exceeds 40%, you’ll keep stocking the inventory.

40% looks like a pretty high number. In real life, you’ll find that organizations are willing to stock that extra unit, for far lower selling probabilities. There is a logical quantifiable reason behind this behavior even though a vast majority don’t know about it. The reason is that profit on immediate sale ($12 in our case) is not the only gain you make from that customer. When a customer walks-in into your store and finds what he/she is looking for, he will continue coming to your store and give you all that future business. This value of all future goods that the customer would buy is called Customer Lifetime Value.

Continuing with the previous example, suppose Customer Lifetime Value at the above store is $100. i.e. if the customer keeps on coming to your store then you stand to profit $100 from that customer. However, if he doesn’t find the product he is looking for, he’ll take this business to your competitors. What is that selling probability at which you’ll keep that unit of inventory? Let’s call it S:

PS = (S x $100) + ((1-S) x -$8)

At the cut-off probability, payoff would be zero.

0 = 108S -100

S = 7%!

Surprising. 93% of the times you are not expecting to sell that one unit and yet you’ll keep it in store because in long run that one customer is going to pay-off by becoming your loyal customer.

So, in a nutshell, keeping extra inventory is determined by probability of us selling it for acquiring a customer lifetime value vs having to write-off the extra inventory.

Some of you might be wondering why we did this analysis for only one unit (and kept on harping upon the point repeatedly). This is because the probability of selling keeps on changing as you add more stock. The probability of selling the 1st unit is very different from probability of selling nth unit.

I’ll be bet my arm that a liquor store in the middle of alcoholic town will sell its first bottle during the first hour of the day. 50th bottle – maybe. 1000th bottle – all bets are off (because I love my arm way too much).

So, coming back to the original point, how do we do this analysis for all of stock and not just one unit? It is the next level of analysis of service level that deserves its own article. Keep tuned in – it’ll be releasing soon.


Whose Inventory Is It Anyway? – by Supply Chain Detective

This is one of the most contentious questions that is often raised in review meetings especially during months of high inventory. We’ve all been there – where all the inventory indicators are in red, warehouses are overflowing with stuff, several leaning Towers of Pisa in the warehouses are a common sight and trucks are waiting for hours to unload their stuff. The supply chain VP’s phone is ringing non-stop and when it seems that nothing can go worse, you suddenly realize that you have an S&OP meeting to attend to.To muddy the waters even further, that one person from finance mumbles how “Inventory” is on the asset side of the balance sheet but still recommending to reduce it as the cost of borrowing is getting higher.So, who is responsible for the inventory after all?As the norm has become with this blog, the answer is – “Well, it’s more complicated than that.”You see, inventory is not a single homogenous bloc that can be assigned or attributed to a single department or function, but a culmination of several direct and indirect causes across the organization.


In fact, Harold S. Geneen, has famously said, apart from his many other famous quotes,

All the problems of business end up in inventory

That’s true. Isn’t it?

Bad forecasting accuracy? – you’ll end up with unsold stock in inventory

Quality problems? – you’ll end up with returns in inventory

Bad roads? – you’ll end with damaged stock in inventory

Failed new product launch? – you’ll end with dead stock in inventory

Bad customer service? – you’ll end with canceled orders and… you guessed it, inventory

Very high customer service? – you’ll need to maintain high safety stock which is…inventory

So, are we doomed to live with this inventory mess forever without figuring out the real culprits? Is there no one who can save us from this impending inventory apocalypse?

Cool down, cut down on dramatics and dial a supply chain detective.

The solution to this mess is actually quite simple. A quick word of advice for SCZs out there – whenever you come across what seems like an insurmountable problem and you are unable to make a headway, start breaking the problem into its individual pieces, trace them back to their source and treat them individually. Once you solve the pieces, put them back together and voila – you have a solution.

For inventory ownership, the problem may look unassailable but let’s start breaking it. The good news is that we already know some of the inventory components. See! The moment we said inventory components, you’d know what is about to come already.

Cycle Stock

The first and often the biggest component of inventory is Cycle stock. It is the inventory that is needed to fulfill the average customer demand between the orders. Simply put, it is all the stock that is meant for selling before you receive the next inbound.

Cycle stock is dependent on two factors = Annual Demand and Inventory turns2.

While annual demand is an independent variable, inventory turns (the ability to churn your inventory) is something that is inherent in organizational strategy which in turn impact supply chain design and policies3 around it.

Let’s take an example –imagine there are two organizations named SavingPrivatePenny Inc (SPP) and FastAndFurious (FAF) Inc. SPP focuses a lot on cost efficiencies while FAF tries to be more responsive to their customers. With these different high-level strategies, SPP has a supply chain policy that prohibits less than 80% FTL load to be shipped. FAF Inc. Doesn’t have such policies and their trucks often go half unutilized.

In this example, SPP will have lower inventory turns vs FAF Inc. By extension – SPP will have higher cycle stock than FAF due to a. Organizational Strategy b. Supply Chain design.

[Some professionals blindly assume that SPP is a better organization than FAF. We’ll discuss this in another article why it’s a wrong pre-assumption without proper assessment.]

In a nutshell, cycle stock seems to be the responsibility of SCM function. However, supply chain design which has set a lower bound on cycle stock, also depends on financial constraints and overall organizational strategy.

Safety Stock

Demand-supply fluctuations are the name of the game and safety stock is the secret weapon in the arsenal of the organization that can help maintain the desired service level despite these fluctuations. However, this weapon comes at a cost. And that cost is inventory in form of safety stock. Higher the target service level, higher is the safety stock you need that may or may not be used that leads to higher inventory. In fact, the service level is the only deciding factor in determining the safety stock.4

So who owns the safety stock?

Simple. Whoever decides on the service levels. In most cases, this is something that is defined by Strategy (since they define the market positioning of the organization) and Sales (as they back-feed the strategy on customer requirements). But it varies widely from organization to organization.

Hence, safety stock inventory component is something that should be owned by strategy or sales. (Or whosoever is taking call on the service level).

Other Miscellaneous Inventory

You’ll notice that even after accounting for cycle stock and safety stock, you’re left with unaccounted inventory. This is something that is often reported as “Excess Inventory”. It is a curious mix of different types of stock that ends up in excess inventory bucket.

Unsaleable Stock: This one is my personal favorite. It consists of all kinds of expired, damaged or otherwise unsaleable stock. The reason this is my favorite is that more often than not this represents a good percentage of overall inventory. And it’s relatively easy to get rid of – you have to simply write it off.

The expired products are due to over-forecasting, and that ownership needs to be shared between the businesses and the demand planning. Damages fall right on SCM and should hit their KPIs.

Interestingly, most of the organizations are aware of this bucket but they don’t want to do the write-offs. Why? Remember when we said at the beginning that inventory is treated like an asset on the balance sheet. Well, write-offs of this inventory, that could be valued millions of dollars on the balance sheet, forces the company to take a huge one-time loss that could be detrimental to its share prices.

This hesitation is natural since no CEO wants to take this dent on the share prices and on his/her bonuses. But keeping this bad stock not only reduces its salvage value but also eats up valuable warehousing space. So, a good SCD must always push for continuously identifying and reducing this unsaleable stock from their supply chains.

This problem was quite visible in the banking industry (Surprise! You can apply SCM concepts to the banking industry too!) in 2008-09 where banking behemoths refused to identify their own toxic assets leading to the biggest global meltdown the world had ever seen since the great depression.

Bonus question: What is “inventory” in banking context? Does EOQ formula hold any significance in such context? What does ‘quantity’ in Economic Order Quantity refers to?

QC Stock: The stock under quality check can be quite significant especially for high-value items or high-tech industry where the quality process can take several days. The ownership of this stock is with Quality, Manufacturing or procurement depending upon your organization. Being in QC doesn’t mean that this inventory can not be reduced. We’ll have an entire post detailing inventory reduction

Promotional Stock: Remember that promotion scheme when you gave out Boyfriend Pillow to your customers for free – when your customers looked long and hard at you wondering if they should be seen in the vicinity of your products; and where, even after six-months of trying to push it down the throat of unsuspecting customers, dealers, wholesalers and mortal enemies, there are still mountains of this abomination lying somewhere in the corner of your warehouse.Yeah, that one.

Dispose it off and put it on marketing’s account. Done.

Blocked Stock: All ERP systems offer stock blocking to prevent multiple sales commitments on the same stock. Once the stock is “blocked” it is unavailable for committing to another customer. However, this functionality is sometimes used to game the system to hoard the stock even for tentative sales. We’ll see various means by which this can be reduced but one thing is clear that the ownership of this inventory lies with the sales.

In conclusion, I want to reiterate that high inventory can be a real big pain for the organizations as it locks up capital, occupies valuable warehousing space and chokes us the free movement of stock though the supply chain. Identification of its ownership goes a long way towards taking the corrective action because if you don’t know who owns it, you will never know how to fix it.

This ownership should be built directly into the KPIs to ensure that right action is taken at the right time.

Do you have something to ask or say about inventory ownership? Please let us know through your comments.


1 It is important to note that balance sheet inventory also includes raw material and WIP inventory. However, in the current article, we are focusing on FG inventory.

2 Hardcore SCDs might argue that the equation is other way round, where inventory turns is calculated from average inventory and COGS. Secondly, average inventory and cycle stock are two different things as former also includes safety stock and other misc inventory like returns, damaged good etc.

While these arguments are correct, in this article’s context we are looking at inventory turns more from a network capability viewpoint and not as a performance metric.

3 If your policies aren’t centered around overall supply chain design and organizational strategy, your supply chain goals will always be in conflict with the organizational goals. For e.g. If you claim to be a super-responsive pizza delivery chain, then your supply chain’s goal can’t be vehicle utilization. You’d have to be prepared for small orders that need to be delivered in 30 mins even if it means carrying one pizza in one van.

4 All other variables in safety stock calculation are not directly controllable e.g. demand variability, Lead Time etc.

As you expected, the meeting is a bloodbath – S&OP chair, with deep burrows on his face, points finger at supply chain, others join in. Supply chain, on the other hand, blames faulty forecasting numbers. Demand planning, in turn, blames the inputs especially the sales projections; and when confronted, sales talks about their top-down targets and narrate in vivid detail how they didn’t receive right marketing support and how Supply Chain didn’t ensure that inventory was at the right place at the right time, thus completing the full circle of shrugging the responsibility of inventory ownership.



The Myth called EOQ -by Supply Chain Detective

All you supply chain zombies (SCZs), who are now vying for the blood of the crackpot who wrote such a blasphemy as the title of this post, take a deep breath, cool down a bit and think back at the time when you last implemented the EOQ formula in its basic form. That is – NEVER.

Hmmm…and now that you are thinking about it, doesn’t it seem strange that one of the most popular supply chain concepts and most widely recognized formula that is literally taught on the first day of supply chain classes in college, is rarely used in the real world?

Well, there is a solid reason behind it. Rather, reasons behind how the real world considerations make our basic EOQ formula difficult to use in practical situations.

And you can too traverse this journey from Supply Chain Zombie to the supply chain detectives by understanding these factors and then tweaking the formulas to make it more suitable for your organization’s context.

But before you scram to your boss to make him salivate with your $545 million formula and start planning o spend that six figure bonus that he’ll shower on you, lets first clear up our basics about EOQ.

For the seasoned Supply Chain Detectives, who understand the basics of EOQ inside out – feel free to skip to the second part of this article. For the rest of us lesser mortals– read on.

The Basic EOQ Formula

While your soporific professor mumbled something about carrying costs and ordering costs in Supply Chain 101 you dozed off while doodling aliens and space rockets in your notebook. Well, don’t worry, we’ve got you covered.

EOQ stands for Economic Order Quantity. Well, what does it mean?

Everyday billions of individuals and millions of organizations across the globe buy stuff. For individuals, it varies from buying eggs, bread & butter to 8 iPhones for a Dog.  And for organizations, it varies from manufacturing raw materials to office supplies, and from toilet papers to million dollar office decorations.

But, unless you are a billionaire owner of that Apple Watch brandishing dog, those billions of individuals and millions of organization must decide on one crucial factor while buying stuff – How much?

It may be intuitive for us to make the decision of ‘how much’ in some simple situations. E.g. eggs – On one hand you don’t want to buy too few eggs to save you trips to the grocery store everyday, one the other hand you also don’t want to buy too many to risk rotting them. And by using this rationale you settle on something in between say 1 week’s worth of supply.

What you are essentially doing here is trying to find a balance between two opposite cost elements – cost of visiting the grocery store too frequently vs cost of overstocking it.

This is what EOQ tells you. It finds the right balance between the Ordering Cost (cost of placing one order. In our example cost of visiting the grocery store once) and Carrying Cost (cost of carrying the inventory – storage costs, cost of capital etc.) mathematically and tells you exactly how much to buy.

Essentially what you are trying to minimize is the total cost of owning something.

Total Cost = Ordering Cost + Carrying Cost — (1)

Let us look at both the components theoretically. Later in this article, we elaborate what actually constitutes ordering and carrying costs from the organization perspective. For now, we’ll stick to formulas.

Ordering Cost

Ordering Cost = Number of orders per year x Cost per order (K)

Number of orders per year = Annual demand (D) / Ordering Quantity (Q)

Carrying Cost

Carrying Cost = Average Inventory (in $) over the year x Inventory Carrying Costs (h)

Average Inventory (in units) = (Q/2)

Average Inventory (in dollar) = (Q/2) x c

[Because we are ordering Q units at a time and it uniformly depletes to zero as the inventory is consumed. Hence, the average inventory is (Q+0)/2]

Carrying Cost = ( Q/2) x c x h

Let’s put back these numbers in total cost equation (1)

Total Cost (TC) = [( D/Q) x K] + [(Q/2) x c x h]

Now do you see why we need to find a sweet-spot of ordering quantity to minimize total costs? No?

Alright, pay close attention to the Q in the above equation. In the first term Q is in the denominator. So when the ordering quantity Q decreases, the first term, Ordering Cost increases. Obviously.

However, in the second term, ordering quantity Q is in the numerator. So when Q decreases, the second term, carrying cost decreases. Obviously.

It is more obvious visually. Below, we have plotted the total cost for various ordering quantities (on the X- axis) and Total cost on Y-axis.

Download the workbook here.

As you can see Total Cost (TC), the purple line, first decreases and then increases with changing Q. Though it is hard to see but the minimum Total Cost occurs at around ordering quantity of 20 units.

Using equation 3 we can derive (see footnotes for a detailed derivation) the order quantity for which the total cost is minimum. Voila! This order quantity is called Economic Order Quantity or EOQ.

We can also put the relevant data that was used to create the graphs above:

D= 100 units per annum, K = $ 2 per order, c = $ 5 per unit and h= 20%

And Q= 20 units that confirms our graph. Hence, we should order 20 units at a time.

This also means that we’ll place 5 orders per year and our average inventory will be 10 units.

Theory is fine but…

Now that you have a solid understanding of the basic EOQ formula, the trick to using it – even the basic version – depends on understanding those variables in the corporate context.

Product Cost (c) : This is the most straightforward variable to find out. Do keep in mind though that we need product’s landed cost and not the price.

Annual Demand (D): Another easy one. Just head down to your forecasting department and ask them politely to give you the projections for the next year. In all probability, they’ll throw a dart at the dart board and give a number to you. If they don’t – come back to your desk and prepare a forecast yourself by using some simple algorithms. That’s another post for another day.

Inventory Carrying Cost (h): Ah! Now we enter into exciting and tricky stuff. The basic premise of inventory carrying cost is any cost that is associated with holding extra inventory on our books. This typically includes cost of capital, cost of holding in warehouse (storage, insurance etc.)

However, this is not an exhaustive list – we should incorporate any other cost or risk that is associated with holding that extra inventory. E.g. risk of obsolescence, risk of damages etc.

Typically inventory carrying costs are taken to be around 17%. But remember, higher cost of capital, increasing risk and dynamic business environment (e.g. risk of design changes frequently) push this number up.

We’ll talk more about these in the next part of this article.

Ordering Cost: How much your organization spends on placing one order. It sounds simple but it is somewhat tricky to calculate. We should only add those ordering cost components that are variable in nature. That is, those costs components that are incurred every time there is an order.

Cost of stationery – ordering cost

Cost of courier – ordering cost

Inspection costs at inbound – ordering cost

Salary of the ordering manager – not an ordering cost

The last one is not an ordering cost because it doesn’t change with the number of orders placed and hence doesn’t impact our EOQ. In a strict sense however, this cost is a step function. Let’s say that up to a certain number of orders 1 ordering manager can handle the work. But for a large increase in orders, you may have to hire more people.


Well, now that we have a proper handle on the basic EOQ formula, we are now ready to take on the real world. But wait! Didn’t we say in the beginning that real world can put a spanner in using this formula in the basic form?

Well, that’s what the next part of this article deals with. Now that you are thorough with the basics , get your Cuban cigars out and get ready to become a true Supply Chain Detective.


Q is Economic Order Quantity

D is Annual demand (in units)

K is Ordering Cost (in $) per order

c is Cost of the product (in $ per unit) and,

h is the inventory carrying cost (as %age of product cost, incurred annually)

In this post we’ll see why EOQ formula should be rarely used in its basic form. And even if you were to use it, you must at least be aware of the caveats and assumptions that have gone into it.

We’ll do that in two parts. First let us challenge some assumptions that we made earlier and then we’ll put in some real world complications that require us to tweak the formula or add in some layers of analysis before we start using the order quantity recommendations.

Assumption #1: Inventory Depletion is uniform

One of the major assumption while deriving the formula was uniform inventory consumption. And that is how we arrived at Q/2 as average inventory. However, this is seldom true. Rate of consumption changes from season to season, week to week and even day to day.

Solution: An ideal solution is to come up with a consumption curve (Inventory vs Time graph) and use it to calculate average inventory over time. However, this may involve doing an integral of a complex curve. If you want to be super-precise then that’d the way to go but there are more practical and easier approximations to this problem that will give you “good” solutions with a lot less effort.

Approximation: Rather than one continuous curve, we can break our time period into two or more sub-periods each having a simpler consumption pattern. For example,  a vast majority of FMCG organizations make most of their sales during the last week of the month. This could be a typical case of student syndrome where sales team is pushing to meet their monthly targets. [This takes a significant toll on supply chain infrastructure and many organizations struggle to manage these last week peaks. We will dedicate a separate post to this topic.]

So, let us say that 50% of the monthly demand is consumed in first three weeks while remaining 50% is consumed in last week itself. In other words, consumption rate during last week is thrice that of first three weeks. Over long-term1, the average inventory can be calculated to be 5Q/8. We leave it to the readers to derive this number. You may notice that this average inventory is higher than (Q/2) that we calculated earlier where the inventory depletion was uniform throughout. This makes sense as earlier we had consumed 75% of the monthly demand in 3 weeks whereas we have only consumed 50% in the current scenario, leaving us with slightly higher inventory.

If we put 5Q/8 as average inventory in Total cost equation:

We can derive modified EOQ as:

Similarly, now you can derive your own EOQ formula given any consumption rate or consumption pattern.

Assumption #2: Cost of the material is constant regardless of quantity

Remember when we wrote the total cost equation as

We deliberately didn’t consider one element of cost in the above equation which was buying cost. We ignored it because it wasn’t relevant as we were spending the same amount annually despite of ordering quantity.

However, this assumption doesn’t hold true especially when buying quantities are large. Suppliers often provide bulk discount options as they save on producing at a scale. In fact a typical supplier quote looks like this:







Price (per)

$ 5

$ 4.75

$ 4.5

$ 4.25

$ 4

As the quantity increases our buying cost decreases significantly. In fact supplier is willing to offer 20% discount if we buy more than 150 units of the product. But is it worth it?

Now, let us rewrite the total cost equation, this time around we’ll have to include the buying cost as it has become relevant.

The product price c* is now a function of Q –

c* = $ 5 per unit (for Q between 1-20)

c* = $ 4.5 per unit (for Q between 21 -50)

…and so on.


Graphical Solution

Let us recreate the chart that we made earlier. This time around, we have an additional line for buying cost.

Download the workbook HERE.

As you can see in the graph above, buying cost is a step-curve. Those “steps” represent the bulk-discounts that supplier has offered. We also see these “steps” in total cost curve (the thick blue line) since it includes the buying cost. You’ll notice that now it is not so easy visually to find the minimum cost point on the total cost curve.

I checked the table that was used to create the graph in the workbook, and it turns out that minimum total cost is $ 461.7 while buying 151 units. Note that this is different from our non-discounted EOQ number where we got the answer as 20 units.

How will you sell this to the CEO? You can’t show derived EOQs and complex graphs, right? Well, you can simply state the following – “Usually, we should only buy 20 units at a time which is roughly one month of supply, however this time around the supplier is giving 20% discount on bulk orders. Sure, this increases our inventory costs a bit but it’ll be more than compensated by the discount.”

Interestingly, the next lowest cost $ 470 occurs at 101 units. So, if your CEO still frowns at you for asking to buy huge inventories, you can always fall back on the second best solution, where incurring 9 dollars extra reduces your inventory from 150 to 100.

[The second best or even third best solution may be more acceptable in some cases. True – that absolute minimum occurs at 151 units but just paying additional 9 dollars we can mitigate some of the unaccounted risks that come along with the additional inventory. This is a typical problem with all kinds of optimization algorithms. They try to reduce the objective function to the absolute minimum, a phenomenon that we describe as chasing the pennies. This is sometimes not desired. And this is where multi-objective optimization comes handy. However, that is another discussion for some other day.]


Analytical Solution

Above, we arrived at the solution by looking at the graph and corresponding data but that’s not feasible especially when large quantities are involved or we don’t have access to spreadsheet software.

While there is no straightforward formula for EOQ with bulk discount because buying cost is a step-function and hence non-differentiable, we still have a step-by-step procedure that can help us arrive at the best quantity.

Step 1: Find normal EOQ for ALL buying costs

In our example, there are five different costs. While we are not showing the detailed calculation their corresponding EOQ values are shown below. Subscript represents the cost(in $ per unit):

EOQ5       = 20 units

EOQ4.75  = 20.5 units

EOQ4.5    = 21.1 units

EOQ4.25  = 21.7 units

EOQ4      = 22.3 units


[Bonus Question: Keeping all the other factors constant, why does EOQ increases as the cost per unit decreases?]

Step 2: Eliminate “Invalid” solutions

Some of the EOQ quantities doesn’t belong to the buying cost. Eliminate them.

EOQ5       = 20 units

EOQ4.75  = 20.5 units X

EOQ4.5    = 21.1 units X

EOQ4.25  = 21.7 units X

EOQ4      = 22.3 units X



Note: You may be left with none or more than one solutions.

Step 3: Calculate and compare total costs for all the valid EOQ solutions and buying qty break-points

Qty Type

Qty (units)

Total Cost ($)




Bulk Qty 1



Bulk Qty 2



Bulk Qty 3



Bulk Qty 4



Bulk Qty 5



Total minimum cost is at Qty 151 which is our answer.


Assumption#3: Inventory Carrying Costs are constant

As briefly touched upon in previous part of this article, inventory carrying cost consists of several components – cost of capital (typically the borrowing rate of your organization), cost of storage (Warehousing costs and salaries) and cost of servicing the inventory (insurance, damages, obsolescence). Though it is highly organization dependent, finding the exact value might be a tricky task. It is usually taken between 17% and 25% depending the nature of the inventory and opportunity cost of capital to the organization.

However, some of these variables are not constant and vary with the quantity of inventory kept in the organization. Couple of examples are below:

Insurance cost: Per unit insurance cost decreases as average inventory increases.

Risk of damages/obsolescence: Risk of damages and obsolescence increases as average inventory increases.


The solution requires some understanding of basic differentiation. If you don’t get it in the first attempt, don’t worry about it too much as we are now

Let us say that by some measure of analytics, one has arrived on a inventory carrying cost equation

Inventory Carrying Cost (h)= r + f(Q)

h = 20% + 2%* ((Q/D)*12)

Don’t get scared by the above equation. It simply states that inventory carrying cost is 20% plus 2% for addition of every month to order quantity. This 2% is attributed to the increasing risk because of incremental inventory. Hence for one month’s inventory, carrying cost = 22%, for two months its 24% and so on.

Putting this in the basic equation


Differentiating both sides by dQ

For min TC,

Simplifying the equation we get,

Replacing the variable values, D = 100 units, c = $ 5, K = $2

This is a cubic equation with three solutions for order quantity Q.

Q= 19.96, -6000, -20

We can reject the negative solutions. Hence, the EOQ for dynamic carrying cost is 19.96.

Note that this is slightly lower than our original solution of 20 units that considered fixed carrying cost of 20%. This seems logical as slight increase in carrying cost is reflected in decreased EOQ.


If you have reached this far, then CONGRATULATIONS! You’ve mastered the science behind ordering quantities and their trade-offs, you are now ready to take on any challenge that anyone in your organization can throw at you. Well, let me scratch that. You are almost ready.

There are some teeny-weeny complications that are often put to question your EOQ numbers. While some of those do not impact our EOQ too much, it is important to be aware of them to pave way for smooth implementation of your ideas. Part 3 of this article is dedicated to those complications and work-arounds.

[At this juncture, some of you might be feeling that we are splitting hairs on EOQ formula. Do yourself a favor and do a back of the envelope calculation on how much total cost changes just by changing the ordering quantity 2% on either side. Total cost swings a lot, even for tiny changes in the ordering quantity.]

Complication #1: Your EOQ is not your supplier’s EOQ
Alright, so you’ve created fancy versions of EOQ models, gathered data on ordering cost and carrying cost through hook or crook, done tons of calculations, and checked and rechecked your numbers. And to your delight, it looks perfect. Not only that, it seems that implementing new EOQ numbers will save a few million dollars for your company every year. But just when it seems that there is nothing between you and that Employee of the Year award, your order is rejected by…the supplier.

But why? Simple. Your order quantity might be the best thing that has ever happened to your organization, it is not feasible for the supplier to manufacture. Supplier has his own manufacturing processes, its own suppliers and his own optimal batch sizes, and the order quantity you are demanding isn’t financially viable for him. For example, remember when we calculated the EOQ of 20 in previous illustration earlier. But what if supplier’s batch run produces only 15 units at a time. This means that he’ll have to run two batches of production to produce 30 units and after fulfilling your “optimal” order of 20, sit on remaining 10 units waiting for your next order. The problem is even worse if his batch size is, say, 50 units.

Well, there are two ways out of the situation – the easy way, where you arm-twist the supplier to your will and push him to absorb the loss which is the most common practice in such situations but in long term results in supplier mistrust, higher inventory at the supplier, and maybe renegotiation of the whole contract.

The slightly difficult way –that will ensure more transparency, collaboration and even bigger savings than the EOQ formula – is called Joint EOQ formula.
[Also known as Joint Economic Lot Size (JELS) formula]

The underlying principle behind Joint EOQ is pretty simple as you might have guessed from its name – it tries to find an optimal EOQ for the supplier-buyer system considered as one. Imagine if supplier was part of your organization – in that case how would you calculate the optimal order quantitiy that needs to be produced.

Let us re-write our total cost equation

Total Cost = Ordering Cost (for both supplier and buyer)+ Carrying cost (for both supplier and buyer)
Where, D is annual demand
Q is the order quantity
Kb is the Ordering cost for the buyer
S is the set-up cost for the supplier
hb, hs Inventory carrying cost for buyer and supplier respectively
cb, cs purchasing cost for buyer and supplier respectively.
We repeat the same procedure of differentiating both the sides by dQ and solve for Q.

The beauty of this JELS quantity is that is leads to even lower cost than what buyer and supplier could have individually achieved. THAT is the power of collaboration right there.

Bonus question: What are the total savings for supplier and buyer combined by moving to JELS than their individual optimal quantities? What should be a fair split of benefits between them?
[For a detailed read on JELS you may want to read this famous paper. Please note that the notations used in the paper are slightly different.]

Complication #2: FTL ≠ EOQ
If you pay your logistics provide by the unit then don’t read further. You can merrily start implementing EOQs and punching those 1 unit orders.

However, if you pay your logistics provider by the trip or the route, you’d notice that EOQ quantities may lead to lower utilization of your vehicles. And since you pay for the whole vehicle whether it has one unit inside it or one hundred, you lose some money on every trip when you order EOQ.

First check whether there are “right-sized” vehicles available with your logistics service provider. Your ideal situation is where EOQ matches exactly with the vehicle capacity.

If EOQ doesn’t align with the vehicle capacity, compare the total cost between partially filled vehicle (LTL) and FTL vehicle. When vehicle is FTL you end up increasing your inventory. It might still be worthwhile to under-utilize the vehicle.

[There are modified EOQ models available where transportation costs are taken as a step function.]
Multi-product ordering : If the supplier deals in multiple products, explore an option to combine multiple products in the same order.

Supplier clustering and multi-pick ups: If there are other suppliers in the vicinity, you may want to club your other orders in the same vehicle. This can also be implemented at buyer’s end where multiple buyers of the same suppliers combine their orders for better efficiencies.

This strategy to maximize vehicle utilization, albeit without EOQ reasons, is quite a common practice for non-competing organizations. Best example, perhaps, is where Nirma sent its heavy detergent packets inside Sintex’s empty water tanks to maximize the vehicle utilization leading to the savings for both the organizations.

Vehicle utilization and idle time reduction is an area of prime focus for the organizations with lot of resources and effort going into improving it. Hence, there will be whole another post to discuss it in detail.

Complication #3: Warehouse Capacities
At times, especially when pushed by deep discounts from the suppliers, EOQ formula may recommend huge buys. However, warehouse capacities are not infinite and handling additional inventory may require additional manpower, equipment or space.

In such rare cases, it is useful to consider warehousing costs as increasing with inventory. This is something we tackled in part 2 where we considered inventory carrying costs to be a function of quantity.

Closing Remarks
Phew! That was a long read. But I hope that has you transformed from a Supply Chain Zombie (SCZ) who used to take orders from bosses and the clients to a Supply Chain Detective (SCD) who doesn’t rely on “thumb rules” and “common practices”.

In fact, the aim of this article wasn’t to cover each and every possible scenario in the book and churn out dozens of formulas but arm you with the thought process and the techniques to handle all sorts of complicated situations that might come your way. If I’ve succeeded in this attempt, do let us know through your comments.

Go ahead, now, change the world.


About Interstate Shipping in India

Unable to ship your products on time to your customers? Are your shipments returning to you after getting stuck atInter-State Checkpoints? Having difficulty in understanding the rules and finding the interstate shipping forms?

If these are the kind of questions that are troubling you with interstate shipping, then we have something incredibly awesome to share with you!

Logistics is crucial for any online store. Delivering your customers’ purchases on time reflects on your store’sefficiency and reliability. Delay in delivering the products is a risk you cannot afford as an online store entrepreneur.

But, living in a big country like India, rules change from State to State. Understanding these rules and finding the respective forms can be a very cumbersome task. That’s why, we bring you an exclusive table to help you sort out the necessary forms to be filled while scheduling a shipment.


   Interstate Shipping Forms and Requirements

Sr. No. List of destination State Business to Consumer (B2C) or Consumer to Consumer (C2C) Business to Business (B2B)
Type of statutory Levy Who is liable/ can pay statutory levy Road permit /paperwork requirement (INR) DOM paperwork exemption limit Status of statutory Levy Paperwork Requirement State VAT website
1 Andhra Pradesh Nil Shipper Invoice Nil
No Statutory levy is paid upfront
CI + VAT Form x/600
2 Andaman & Nicobar Nil Shipper Invoice Nil Shipper Invoice
3 Arunachal Pradesh Entry Tax Consignee CI +DG -01 (TPT doc) <10,000 CI + DG 01
4 Assam Entry Tax Consignee CI+Form 62 <20,000 CI + VAT Form 61
5 Bihar VAT Consignee CI+ Form D IX – on line Nil CI + VAT Form D IX
6 Chandigarh Nil Shipper Invoice Nil Shipper Invoice
7 Chattisgarh Nil Shipper Invoice Nil CI & Declaration from Cnee
8 Dadra & Nager Haveli Nil Shipper Invoice Nil Shipper Invoice
9 Daman & Diu Nil Shipper Invoice Nil Shipper Invoice
10 Delhi Nil Shipper Invoice Nil CI + T2
11 Goa Nil Shipper Invoice Nil Shipper Invoice
12 Gujarat Nil CI + VAT Form 403 Nil CI + VAT Form 403
13 Haryana Nil Shipper Invoice Nil Shipper Invoice
14 Himachal Pradesh Entry Tax Consignee / Carrier Shipper Invoice Nil Shipper Invoice
15 Jammu & Kashmir Entry Tax Consignee / Carrier Shipper Invoice <5,000 CI + VAT From 65
16 Jharkhand Nil CI + VAT Form 502 Nil CI +VAT Form 504 G
17 Karnataka Nil Invoice & Declaration Nil CI + e-Sugam
18 Kerala Nil CI + Form 16 <5,000 Shipper Invoice
19 Lakshadweep Nil Shipper Invoice Nil Shipper Invoice
20 Madhya Pradesh Nil CI+ VAT Form 50 online Nil CI + VAT Form 49 online
21 Maharashtra Octroi Carrier Shipper Invoice <150 Shipper Invoice + LBT/Octroi
22 Manipur Nil CI + VAT Form 37 Nil CI + VAT Form 27
22 Meghalaya Nil CI+ Special permit Nil CI + VAT Form 40
23 Mizoram Nil CI + VAT Form 34 Nil CI+VAT From 33
24 Nagaland Nil CI+ VAT Form 23 CI+ VAT Form 23 (online)
26 Orissa Entry Tax* Consignee Shipper Invoice Nil CI+ VAT Form 402 (online )
27 Pondicherry Nil Shipper Invoice NA Shipper Invoice
28 Punjab Entry Tax Shipper Invoice Nil Shipper Invoice
29 Rajasthan Entry Tax Consignee CI + Declaration Nil CI + VAT Form 47/47A ( online )
30 Sikkim Nil CI + VAT Form 26 Nil CI+ VAT From 25
31 Tamil Nadu Nil Shipper Invoice Nil Shipper Invoice
32 Telangana Nil Shipper Invoice Nil CI + VAT Form x/600
323 Tripura Nil CI+ VAT Permit CI+ VAT FROM XXIV
34 Uttar Pradesh Nil CI + VAT Form 39 Nil CI +VATe-sancharan
35 Uttrakhand Nil CI + Vat Form 17 <5,000 CI + VAT Form 16
36 West Bengal Entry Tax* Carrier Shipper Invoice + VAT Form 50A Nil CI + VAT Form 50A

From this table, find the State to which you are shipping your products. Cross check the conditions to know what form is required. Get the forms from the links given in the table. The links to the state government have been provided in the table.

How and when do you use these forms?

You will need to provide the filled forms to the person arriving for the pick up. The logistic company will produce this form for you at the check points. Rest assured, as your products travel safe to reach your customers at far off places.

Thus, you can now send your products to your lovely customers with ease and make sure the shipments don’t return because of a lack of documents. Happy selling! 🙂

Did we miss anything? Do let us know.

How VAT works?

VAT — Value-Added Tax — is the biggest tax reform in the last 50 years of independent India and will change forever the way traders do their business.

But do you understand VAT? Don’t you need advice on the new VAT laws and how they affect your business? No need to worry, help is at hand.

Kul Bhushan, a newspaper editor — with over 30 years of experience — who specialises in presenting complicated economic and business issues in simple, reader-friendly language, has come up with a book — How To Deal With VAT — which addresses all the questions you may have about this tax.  The book has a foreword by Finance Minister P Chidambaram.

Here’s an extract from the book explaining how VAT works.

Some VAT registered traders may overcharge their customers because they do not understand the correct workings of VAT on prices or are deliberately using VAT as an excuse for increasing prices.

A trader registered for VAT effectively pays VAT only at one stage when he sells his goods.

This tax is the only amount, which has an effect on his selling price which includes VAT. The VAT that he has paid as a part of his purchase price is charged on him by his suppliers.

This is not a cost to him because he gets it back by deducting it from tax on his sales (Output Tax). Therefore, VAT should have a minimum impact on his selling prices.

If you supply designed goods and your annual ‘taxable turnover’ is more than Rs 5 lakh, you become a taxable person and must register for VAT.

Your taxable turnover is the total value of all taxable supplies (including ‘zero-rated supplies’) made in India or imported into India while increasing your business. ‘Exempt supplies’ do not count towards your taxable turnover. Both ‘zero-rated supplies’ and ‘Exempt supplies’ are listed in the VAT Schedules.

If you supply Vatable goods, the ‘taxable turnover’ that must be taken into account is the combined turnover of both these activities.

If you are a Vatable person, you must charge VAT whenever you make a taxable supply. The supply is your output and the tax you charge is your Output Tax. Similarly, the purchase is your input and the tax you pay is the Input Tax.

VAT Returns

VAT Returns are filed every month or every quarter depending on the amount of VAT you pay. The normal rule is that if you pay less than Rs 15,000 for VAT every month, a VAT Return is to be filed every quarter.

It is all at the discretion of the VAT officer. At monthly or quarterly intervals on your VAT Return, you should subtract your Input Tax (attributable to taxable supplies only) from your Output Tax and pay the difference to the VAT Commissioner.

If your Input Tax is greater than your Output Tax you can carry over the difference as a credit to your next VAT Return. In certain circumstances, the Commissioner may pay you any excess if he is satisfied that suchan excess is a regular feature of your business.

Issuing Tax Bills and Invoices

According to VAT law, you cannot sell any goods without a sales document. This document can be a small cash memo or a cash sale or a bill for cash transactions issued at, or before, the time when the cash is received.

The prices mentioned on these sale documents should include VAT and the words ‘Price includes VAT’ must be printed on them. These documents are suitable for retailers such as grocers and chemists.

You must give the original to the customer and keep a duplicate. At the end of each business day, you can total the cash sales and enter it in your Sales Ledger.

For selling on credit, you are required to provide the purchaser with a tax invoice at the time of supply in respect of that supply. When you receive a deposit as advance payment for a booking, a tax invoice should be issued at the time such deposit is received.

All tax invoices should be serially numbered and issued in serial number order. They must include the following information:

  • Your name, address, TIN.
  • Serial number of the invoice
  • Date of the invoice
  • Date of the supply, if different from invoice date
  • Name and address of the person to whom the supply was (will be) made
  • Description, quantity and price of the goods and services being supplied or to be supplied (in case of deposit)
  • Rate and amount of VAT charged on each of these goods and services
  • Details of whether the supply is a cash or credit sale
  • Details of cash or other discounts, if any, that apply to the supply
  • The total value of the supply and total amount of VAT charged
  • Number of the vehicle transporting these goods, if applicable
  • The customer’s PAN must be shown if the sale is over Rs 50,000.

However, if you are a retailer or you are primarily supplying taxable goods to unregistered persons, you will be required to issue a simplified tax invoice.

Simplified Tax Invoices

All simplified tax invoices shall be serially numbered and shall be issued in the order of the serial number. They must include the following information:

  • Your name, address and TIN
  • Serial number of the invoice
  • Date of the invoice
  • Brief description of the goods and services supplied.
  • Total amount charged to the customer including VAT and
  • A clear statement that the price includes VAT.

Value for Tax

The value for tax of a supply is the consideration or money paid. Consideration for a supply includes payment in money and / or in kind for the supply. The value for tax will be:

The full money value paid for the supply where consideration is wholly an amount of money, i.e., the value less any discounts allowed. Instalment payment do not affect the tax value or the point. Tax is due in full at the time of supply on the full (net) value of the article in question.

Open market value of the goods in question where consideration is not wholly an amount of money. This is the price, excluding VAT, which customers ordinarily have to pay for a supply if money was the only consideration.

Value for duty plus the duty — for imported goods at the time gods – cleared for use into the country or at the time of removal from warehouse.

Financial charges incurred by a person who purchases taxable goods on hire purchase business are excluded from the taxable value.

Similarly, interest incurred from late payment of the price of a taxable supply of goods is excluded from taxable value.

How VAT is Misused

Let us take two examples to understand the working of VAT.

Example A shows the pricing structure of a trader who uses VAT as an excuse for overcharging his customers.

Example B shows the pricing structure of a trader who does not use VAT as a tool for price escalation. For both examples, the relative data is:

  • Basic purchase of goods: Rs 10,000
  • 12.5 per cent VAT of the basic purchase price: Rs 1,250
  • Overheads related to the goods: Rs 100
  • Profit margin 20 per cent.


Example A (Rs)
Basic purchase price 10,000
Add 12.5 per cent VAT 1,250
VAT inclusive purchase price 11,250
Add overheads 100
Total 11,350
Add 20 per cent profit margin 2,270
Basic selling price 13,620
Add 12.5 per cent VAT 1,703
VAT inclusive selling price 15,323


Example B (Rs)
Basic purchase price 10,000
Add 12.5 per cent VAT 1,250
VAT inclusive purchase price 11,250
Less VAT input 1,250
VAT free purchase price 10,000
Add overheads 100
Total 10,100
Add 20 per cent profit margin 2,020
Total 12,120
Basic selling price 13,620
Add 12.5 per cent VAT 1,515
VAT inclusive selling price 13,635

The VAT of 12.5% is charged on the ‘Total’. Thus the VAT inclusive selling price will be ‘Total’ + ‘VAT.’

You will note that in Example A, the trader has overcharged his customer to the extent of Rs 1,688. Thus a trader is advised to adopt Example B as a guideline and nt overcharge the consumer. If he does, he will lose his customers before long.

VAT Account

You are required to maintain a VAT account as part of your records. This should have details of your Output Tax, Input Tax and under or over declaration in the previous VAT accounting period(s).

A specimen of such a VAT account is given below.

VAT Accounting for Filing VAT Return for April to June 2005

Purchases (in Rs )
Period Purchases Input VAT paid Total Total
April-June 100,000.00 12,500.00 112,500.00


Sales (in Rs )
Period Purchases Input VAT paid Total Total
April-June 120,000.00 15,000.00 135,000.00

Hence, VAT to be paid is Output VAT less Input VAT or Rs 15,000 – 12,5000 = 2,500.

VAT Accounting with Opening Stock for April to June 2005
(As per the guidelines of VAT White Paper of 17 January 2005.)


Opening Stock on 1 April 2005 Rs 500,000
Less Tax Free Stock Rs 300,000
Balance Rs 200,000
Sales Tax @ 10% paid before VAT Rs 20,000

This credit of Rs 20,000 has to be carried forward in VAT account shown below.

Purchases (in Rs )
Period Purchases ST paid Input VAT paid
Opening stock 500,000.00 20,000.00
April-June 100,000.00 12,500.00
Sales (in Rs )
Period Sales Input VAT paid Total
Opening stock 120,000.00 15,000.00 135,000.00

Hence, the credit of Sales Tax paid on opening stock (Rs 20,000) can be claimed in addition to Input Tax payable for VAT of 12,500.

This means the total tax paid (Sales Tax + VAT) will be Rs 20,000 + 12,500 = Rs 32,500.

In filing the VAT Return, the VAT payable is Rs 15,000 as per sales record.

This has to be deducted from the total tax paid of Rs 32,500, leaving a balance of Rs.17,500 to be claimed in the next VAT Return.

VAT Accounting For Inter-State Supplies and Taxes

Raw materials supplier in Mumbai sells to manufacturer in Delhi.

Delhi manufacturer Rs
Cost Price 10,000
Central Sales Tax @ 4% 400
Total Cost 10,400

Delhi manufacturer cannot claim central Sales Tax @4% of Rs 400 against Form C. hence his cost price will increase by Rs 400.


Manufacturer’s Cost Price 10,400
Value Added 2,000
Selling Price 12,400
VAT 1,550
Cost 13,950

Manufacturer pays VAT of Rs 1,550.00.


Wholesaler’s Cost Price 12,400
Value Added 2,000
Selling Price 14,400
VAT @ 12.5% 1,800

Wholesaler pays VAT of Rs 250. This is arrived at by deducting Rs 1,550 that he paid to manufacturer from Rs 1,800 that he collected brown i.e., 1,800.00 – 1,550.00 = 250.00.

Retailer’s Cost Price 14,400
Value Added 2,000
Selling Price 16,400
VAT @ 12.5% 2,050

Retailer pays VAT of Rs 250. This is arrived at by deducting Rs 1,800 that he paid to manufacturer from Rs 2,050.00 that he collected, i.e., Rs 2,050-1,800 = 250.


Customer Price 16,400
VAT @ 12.5% 2,050
Price with VAT 18,450

Cross Checking

Total VAT paid will be Rs 1,550 (Manufacturer) + 250 (Wholesaler) + 250 (Retailer) = Rs 2,050.

Usage of debit note and credit note

Debit Note Vs Credit Note

Purchasing and Selling of goods are very common in day to day life, and in the same way, returns of goods are also a very usual thing nowadays. Debit Note and Credit Note are used while the return of goods is made between two businesses.

Debit Note is issued by the purchaser, at the time of returning the goods to the vendor, and the vendor issues a Credit Note to inform that the returned goods have been received by him. People are quite puzzled when they are asked to distinguish the two terms. So, here in this article we are going to explain you the differences between a Debit Note and Credit Note.


Debit Note

It is a note issued by the vendor making the supply in the case where the consideration for the supply is increased after an invoice has already been issued. This can be the result of, amongst others; the reduced rate of VAT being used instead of a standard rate of tax (14%), a wrongly reduced quantity of goods is invoiced etc.

The debit note should contain the following information:

  • the words ‘debit note’ in a prominent place;
  • the commercial name, postal address, physical address, Taxpayer Identity Number of the vendor making the supply;
  • the commercial name, postal address, physical address, Taxpayer Identification Number of the vendor receiving the supply;
  • the date of issue of the debit note;
  • a brief explanation of the circumstances which gave rise to the issue of the debit note;
  • sufficient information to identify the taxable supply to which the debit note relates;
  • the taxable value of the supply shown on the VAT invoice, the correct taxable value, the difference between the two amounts and the VAT relating to the difference (that is, the VAT overcharged).

Credit Note

It is a note issued by the vendor making the supply in the case where the consideration for the supply is reduced after an invoice has already been issued. This can be the result of, amongst others, cancellation of the supply, a discount offer etc.

The credit note should contain the following information:

  • the words ‘credit note’ in a prominent place;
  • the commercial name, postal address, physical address, Taxpayer Identity Number of the vendor making the supply;
  • the commercial name, postal address, physical address, Taxpayer Identification Number of the vendor receiving the supply;
  • the date of issue of the credit note;
  • a brief explanation of the circumstances which gave rise to the issue of the credit note;
  • sufficient information to identify the taxable supply to which the credit note relates;
  • the taxable value of the supply shown on the VAT invoice, the correct taxable value, the difference between the two amounts and the VAT relating to the difference (that is, the VAT overcharged)

Gross Profit vs. Operating Profit vs. Net Profit

At the core, profit is earnings minus expenses. However, we want to bifurcate and come up with various variations of profit to understand the business better. Therefore, at the first level, we have gross profit.

Gross Profit is nothing but ‘Sales – COGS’

This shows how much profit are we earning without considering our expenses and only considering the cost of the product that we are selling.

Next comes the Net Profit.  Net Profit is ‘Gross Profit – Total Expenses’. The expenses include all the direct and indirect expenses incurred to achieve that sales.

However, some of these expenses might be operational related and some of the expenses may be stuff like taxes. Therefore, we sub-divide it again to understand it better. S, we first subtract all the operating expenses and call it as operating profit. Later, we subtract the rest of the expenses and call it as Net Profit or Bottom Line. This is what is going into the bank.