Discount and festival offer calculator

Buy 1 get 1 free is a 50% discount, buy 2 get 1 is 33.33% and buy 3 get 1 is 25%: the formula is free items divided by total items. Enter your price, cost and GST rate below to compare % off, flat ₹ off and buy X get Y offers by real discount and the profit each one leaves.

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1. The item

Selling price per item (₹, with GST)

Your cost per item (₹, without GST)Optional. Needed for profit.

GST rate

2. The offer

Type of offer % off Flat ₹ off Buy X get Y

Buy (X)

Get (Y)

Discount on the Y items (%)100 = free. 50 = half price.

Items given: 3
Customer pays: ₹1,998.00
Customer saves: ₹999.00
Real discount: 33.33%
Price per item: ₹666.00
GST on the bill: ₹95.14

Your profit on this deal: ₹552.86
Same items at full price: ₹1,504.29
Margin on the deal: 29.05%

You give a real discount of 33.33% and earn ₹552.86 on 3 items (₹184.29 per item) instead of ₹1,504.29 at full price.

3. Compare common festival offers

Offer	Real discount	Customer pays	Profit per deal	Profit per item
10% off	10%	₹899.10	₹406.29	₹406.29
20% off	20%	₹799.20	₹311.14	₹311.14
Buy 1 get 1 free	50%	₹999.00	₹51.43	₹25.72
Buy 2 get 1 free	33.33%	₹1,998.00	₹552.86	₹184.29
Buy 3 get 1 free	25%	₹2,997.00	₹1,054.29	₹263.57
Buy 1 get 2nd at 50% off	25%	₹1,498.50	₹527.14	₹263.57

Same item, price and cost as above. Profit is after GST, before rent and salaries.

How to use it

Enter the item. Type the selling price with GST, your cost without GST and the GST rate.
Pick the offer. Choose % off, flat ₹ off on the bill, or buy X get Y (free or at a % off) and fill in the numbers.
Read the real discount. See what the customer pays, the real discount %, GST on the bill and your profit on the deal.
Compare offers. Check the table to see which common festival offer costs you the least for the same item.

Offer formulas

Offer	Real discount	Example (item ₹999)
% off	The % itself	20% off → pays ₹799.20
Flat ₹ off	Flat ÷ bill before discount × 100	₹200 off 2 items → 10.01%
Buy X get Y free	Y ÷ (X + Y) × 100	Buy 2 get 1 → 33.33%
Buy X, Y at Z% off	Y × Z ÷ (X + Y)	Buy 1, 2nd at 50% off → 25%
Profit on the deal	Paid × 100 ÷ (100 + GST) − items × cost	Buy 2 get 1, 5% GST, cost ₹450 → ₹552.86

Plan your season with the festival sale promotions guide, check margins with the profit margin calculator and read how GST works on discounts.

Questions

What discount is Buy 1 Get 1 free?

50%. The customer gets two items for the price of one. Buy 2 get 1 free is 33.33% off, buy 3 get 1 free is 25% off. The formula is Y ÷ (X + Y) × 100 when all items have the same price.

Which is better for the shop: 20% off or buy 2 get 1?

Buy 2 get 1 is a 33.33% discount, deeper than 20%, but it sells three items at once. On an item with a 50% margin, both still make money; on a 30% margin item, buy 2 get 1 sells below cost. Use the comparison table with your own cost.

How is GST charged on a buy one get one free offer?

CBIC Circular No. 92/11/2019-GST says buy one get one free is not a free supply: the customer pays for both items together, so GST is charged on the price actually paid, spread across the items. You can still claim input tax credit on the free item.

Is GST charged before or after a discount?

After, when the discount is shown on the invoice at the time of sale. GST is charged on the price the customer actually pays. That is why a 20% discount also lowers the GST on the bill.

How do I work out the real discount on a flat ₹ off offer?

Divide the flat amount by the bill total before discount. ₹200 off a ₹1,998 bill is 200 ÷ 1,998 × 100 = 10.01%.

What is the most I can discount without a loss?

Your margin. If you buy at ₹450 (without GST) and sell at ₹999 with 5% GST, your price without GST is ₹951.43 and your margin is about 52.7%. A real discount above that sells below cost.

Run offers without calculating at the counter

RichPOS applies automatic offers at billing, such as bill % off and buy X get Y, and charges GST on the discounted price. Send the offer to customers on WhatsApp.

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