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Profit Margin Formula for Shops: Margin vs Markup, GST and Selling Price
The profit margin formula is profit divided by selling price, not by cost. Here is the difference from markup, a conversion table, how to set a price for a target margin, how GST changes the sum, and worked kirana examples.
AI overview
Quick answer- Profit margin = (Selling price − Cost price) ÷ Selling price × 100. Margin is measured against the selling price.
- Markup = (Selling price − Cost price) ÷ Cost price × 100. Markup is measured against the cost. What school maths calls "profit percentage" is markup.
- The same rupee profit gives a smaller margin than markup. Buy at ₹80 and sell at ₹100: profit ₹20, margin 20%, markup 25%.
- To hit a target margin, divide; don't multiply: Selling price = Cost ÷ (1 − margin). For a 20% margin on an ₹80 cost, that is ₹80 ÷ 0.8 = ₹100. Adding 20% to cost gives ₹96, only a 16.67% margin.
- GST-registered regular dealer: work out margin on prices before GST, because the GST you collect is not your money.
- Composition or unregistered shop: the GST you paid on purchases is part of your cost.
- Discounts eat margin fast. A 10% discount on an item with a 20% margin halves your profit on it.
Summarize with AI
On this page 9 sections
Search "profit margin formula" and you get finance pages about net income, revenue and income statements. That is fine for a company report, but it does not help someone deciding what to charge for a packet of biscuits. Shopkeepers have three practical questions: how much am I really making on this item, what price should I set, and why is there less money at the end of the month than my margins promised?
This guide answers those with shop numbers. It covers the margin formula and the markup formula and why mixing them up costs money, a conversion table, the selling price formula for a target margin, where GST fits (it is different for regular, composition and unregistered shops), worked kirana examples, and what a discount really does to your margin. Every number has been checked.
The two formulas, side by side
| Profit margin | Markup (profit %) | |
|---|---|---|
| Formula | (SP − CP) ÷ SP × 100 | (SP − CP) ÷ CP × 100 |
| Answers | "Of every ₹100 of sales, how much is profit?" | "How much did I add on top of cost?" |
| Example: buy ₹80, sell ₹100 | 20 ÷ 100 = 20% | 20 ÷ 80 = 25% |
| Used for | Comparing items, monthly profit, break-even | Quick pricing at the counter |
Both are correct; they measure different things. The trouble starts when a shopkeeper decides "I want 20% on everything", prices by adding 20% to cost (markup), and then plans the month expecting 20% of sales as profit (margin). The real margin is 16.67%, and the shortfall shows up as "where did the money go?"
Margin to markup conversion table
| Markup on cost | Margin on sale |
|---|---|
| 10% | 9.09% |
| 20% | 16.67% |
| 25% | 20% |
| 33.33% | 25% |
| 50% | 33.33% |
| 100% | 50% |
And the other way round:
| Margin you want | Markup you must add |
|---|---|
| 10% | 11.11% |
| 15% | 17.65% |
| 20% | 25% |
| 25% | 33.33% |
| 30% | 42.86% |
The conversion formulas are Margin = Markup ÷ (1 + Markup) and Markup = Margin ÷ (1 − Margin), using decimals (20% = 0.20).
Selling price formula for a target margin
Selling price = Cost price ÷ (1 − target margin)
Example: a 1 kg pack of toor dal costs you ₹120 and you want a 15% margin.
- Correct: ₹120 ÷ 0.85 = ₹141.18. Profit ₹21.18, margin 15%.
- Common mistake: ₹120 × 1.15 = ₹138. Profit ₹18, margin 18 ÷ 138 = 13.04%.
On one pack the gap is ₹3.18. On 300 packs a month it is ₹954, from one item.
Where GST fits into the profit margin formula
This is the part generic finance pages leave out, and it depends on how your shop is registered.
Regular GST-registered shop: work before GST
You collect GST from the customer and claim the GST you paid on purchases as input tax credit, then pay the difference to the government. Neither amount is yours, so use prices before GST on both sides.
Example: biscuits with an MRP of ₹10, which includes 5% GST. Your purchase price is ₹8.00 plus 5% GST.
- Price before GST: ₹10 ÷ 1.05 = ₹9.52
- Cost before GST: ₹8.00
- Real profit: ₹9.52 − ₹8.00 = ₹1.52 a packet
- Margin: 1.52 ÷ 9.52 = 16%
If you do the sum on GST-inclusive prices (₹10 − ₹8.40 = ₹1.60), the margin still comes out at 16%, because the GST rate is the same on both sides. But the rupee profit is overstated: ₹1.60 instead of ₹1.52. The 8 paise difference is 5% GST on your margin, which you owe the government. On a lakh of biscuit sales that is a few hundred rupees you counted as profit and then paid out as tax.
To set a GST-inclusive price from a target margin, calculate the price before GST first, then add GST. For the dal above: ₹141.18 × 1.05 = ₹148.24. Round to ₹149 and your price before GST becomes ₹141.90, a margin of 15.44%. Our guide on how to calculate GST has the add-GST and remove-GST formulas.
Composition dealer: GST on purchases is cost
A composition dealer cannot claim input tax credit and cannot charge GST on the bill. Instead it pays a small tax on turnover, 1% for traders (0.5% CGST + 0.5% SGST).
Same biscuits, sold at MRP ₹10:
- Cost including GST: ₹8.00 + 5% = ₹8.40
- Composition tax: 1% of ₹10 = ₹0.10
- Profit: ₹10 − ₹8.40 − ₹0.10 = ₹1.50
- Margin: 1.50 ÷ 10 = 15%
Unregistered shop: GST on purchases is cost too
An unregistered shop pays GST on what it buys but cannot claim it back or charge it. Cost is ₹8.40, sale is ₹10, so profit is ₹1.60 and margin is 16%.
MRP is a ceiling
On packaged goods you cannot charge more than the printed MRP, and MRP includes GST. So the distributor's price decides your margin more than your pricing does. When a supplier offers a "scheme", work out the margin before GST on the new landing cost; a free-goods offer is worth less to you than it looks if the items sit unsold.
Worked kirana examples
For a regular GST-registered shop, with all prices before GST:
| Item | Buying price (₹) | Selling price (₹) | Profit (₹) | Margin | Markup |
|---|---|---|---|---|---|
| Rice, 5 kg bag | 400.00 | 440.00 | 40.00 | 9.09% | 10% |
| Bathing soap | 32.00 | 38.00 | 6.00 | 15.79% | 18.75% |
| Biscuits, pack | 8.50 | 10.00 | 1.50 | 15% | 17.65% |
| Sunflower oil, 1 L | 140.00 | 150.00 | 10.00 | 6.67% | 7.14% |
Two lessons are hiding here:
- Staples earn rupees, not percentages. The oil makes ₹10 a bottle at a thin 6.67%; the soap makes ₹6 at nearly 16%. Staples bring customers in, and higher-margin items are where profit grows.
- Your shop's margin is a blend. If most of your sales are rice and oil, your overall margin will sit near the bottom of the table however good your soap margin is.
Typical kirana margin ranges
These are rough ranges that shopkeepers and distributors commonly mention. They vary a lot by city, supplier, brand and scheme, so treat them as a starting point, not a benchmark:
| Category | Rough margin |
|---|---|
| Rice, atta, sugar, dal, edible oil | 3% to 10% |
| Dairy (packaged milk, curd) | 4% to 8% |
| Packaged FMCG (biscuits, soap, toothpaste) | 8% to 15% |
| Personal care, cosmetics, home care | 15% to 25% |
| Loose spices, dry fruits, own-packed items | 15% to 30% |
For practical ways to move your blend upwards, see our guide on how to increase kirana store sales.
What a discount does to your margin
Discounts feel small to the customer and big to you. Take an item that costs ₹80 and sells at ₹100: a 20% margin, ₹20 profit.
| Discount | New price | Profit | Margin | Extra sales needed for the same profit |
|---|---|---|---|---|
| None | ₹100 | ₹20 | 20% | – |
| 5% | ₹95 | ₹15 | 15.79% | 33% more units |
| 10% | ₹90 | ₹10 | 11.11% | twice the units |
A 10% discount on a 20% margin item cuts profit per unit in half, so you must sell double to stand still. Discount items with healthy margins, or use offers like "buy 2, get ₹5 off" that raise the bill size.
Gross margin, net margin and break-even
Everything above is gross margin: selling price minus what you paid for the goods. Your shop also has running costs such as rent, electricity, a helper's salary and wastage. What is left after those is net profit, and net profit ÷ sales is your net margin.
Example: in one week a shop sells ₹1,00,000 at a blended 12% gross margin, so gross profit is ₹12,000. Weekly running costs are ₹7,000. Net profit is ₹5,000, a 5% net margin.
Break-even sales = Monthly fixed costs ÷ Gross margin
If rent is ₹15,000, electricity ₹3,000 and a helper's salary ₹12,000, fixed costs are ₹30,000 a month. At a 12% blended margin, break-even is ₹30,000 ÷ 0.12 = ₹2,50,000 of sales a month, about ₹8,333 a day over 30 days. Every rupee of sales above that adds 12 paise of profit; every rupee below it loses money.
If you are planning a new shop, run this sum before you sign the rent agreement. Our how to start a kirana store guide covers the rest of the setup costs.
Tracking margin without a calculator
Margin maths is easy for one item and tiring for three hundred. A billing app that knows your buying prices does it for you. In BillZap, when you add a product with its buying price, the app shows the profit margin next to it. Reports show your sales and profit, and low-stock alerts tell you when a fast-moving item is running out, so you don't lose sales on the products that earn most. The bills themselves are GST tax invoices, bills of supply or plain bills depending on your registration, with CGST and SGST worked out; for GST rates by item, see our GST rates list. Our kirana store billing app guide covers what else to look for.
FAQ
What is the formula for profit margin?
Profit margin = (Selling price − Cost price) ÷ Selling price × 100. If you buy at ₹80 and sell at ₹100, the margin is ₹20 ÷ ₹100 = 20%.
What is the difference between margin and markup?
Margin divides the profit by the selling price; markup divides it by the cost price. The same ₹20 profit on an ₹80 item is a 20% margin but a 25% markup. Markup is always the larger number.
How do I calculate the selling price for a 20% margin?
Divide the cost by (1 − 0.20). For a ₹120 cost: ₹120 ÷ 0.80 = ₹150. Adding 20% to cost (₹144) gives only a 16.67% margin.
Should I include GST when calculating profit margin?
If you are a regular GST-registered dealer, no. Use prices before GST, because GST collected is owed to the government and GST paid is claimed back. If you are a composition dealer or not registered, include the GST you paid on purchases in your cost, because you cannot claim it back.
What is the profit percentage formula?
Profit percentage = Profit ÷ Cost price × 100. This is the same as markup. Selling at ₹100 something that cost ₹80 is a 25% profit percentage.
What is a good profit margin for a kirana store?
It depends on what you sell. Staples like rice, atta and oil often earn single-digit margins, while personal care and loose items can earn 15% to 30%. A store's blended gross margin usually depends on how much of its sales come from staples.
How does a discount affect my margin?
It comes straight out of profit. On an item with a 20% margin, a 10% discount cuts profit per unit from ₹20 to ₹10, so you need to sell twice as many to earn the same.
The bottom line
Measure margin against the selling price, set prices by dividing cost by (1 − margin), and keep GST out of the sum if you are a regular dealer. Then look at your blend, not just your best item, and check that monthly sales clear your break-even with room to spare. Those few habits explain most of the gap between the profit a shop expects and the profit it gets.
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