It's festive sale season, and every app and shop is shouting numbers: "Flat 50% + extra 20% off!", "Buy 2 Get 1 Free!", "10% instant bank discount!", "Up to 80% off!". Some of these deals are excellent; others are much smaller than they look. The good news is that a few minutes of simple maths is enough to see through all of them. This guide explains how stacked discounts, combo offers and bank offers really work, with worked examples, so you know exactly what you're saving before you click "Buy".
Stack a discount, extra discount, coupon and bank offer to see the true final price and total discount.
Open the discount calculator →Rule 1: Stacked discounts don't add up
When a sale says "50% off + extra 20% off", the extra 20% is taken from the already halved price – not from the original. So:
- ₹1,000 with 50% off → ₹500.
- Extra 20% off ₹500 → ₹100 off → ₹400.
- Total discount: ₹600 out of ₹1,000 = 60%, not 70%.
The formula is Total discount = 1 − (1 − first) × (1 − second). A few common combinations:
| Offer | Looks like | Real total discount |
|---|---|---|
| 30% + extra 10% | 40% | 37% |
| 40% + extra 10% | 50% | 46% |
| 50% + extra 20% | 70% | 60% |
| 60% + 10% + 5% | 75% | 65.8% |
Stacked discounts are still good deals – just not as good as adding the numbers suggests.
Rule 2: Check the MRP and the usual price
A discount is only as real as the price it starts from. If a shirt that normally sells for ₹1,499 is listed with an MRP of ₹2,999 and "60% off", you pay about ₹1,200. That's a real saving of about ₹300 – around 20% off the usual price, not 60%.
Before a big sale, it's worth noting the prices of things you plan to buy. Many shoppers also use price-history tools or simply compare the same product across two or three stores. Remember that in India the MRP already includes GST, so a shop can't add GST on top of it.
Rule 3: "Buy X Get Y" offers
Combo offers are discounts in disguise. Assuming all items cost the same:
- Buy 1 Get 1 Free = 50% off each item.
- Buy 2 Get 1 Free = about 33% off each item (you pay for 2 out of 3).
- Buy 1 Get 1 at 50% = 25% off each item (you pay 1.5 for 2).
- Buy 3 for the price of 2 = about 33% off, the same as Buy 2 Get 1.
When items have different prices, the free one is usually the cheapest, so the real discount is smaller. These offers only save money if you actually need the extra items.
Rule 4: Bank offers have caps
"10% instant discount up to ₹1,500 on XYZ Bank cards" means you get 10% off – but never more than ₹1,500. The full 10% only applies to bills up to ₹15,000.
- Bill ₹12,000 → ₹1,200 off (10%).
- Bill ₹30,000 → only ₹1,500 off (5%).
Also check the minimum purchase amount, whether it works with EMI or only full payment, and whether it's an instant discount (reduced at checkout) or cashback (credited later, sometimes as points or wallet balance with its own conditions).
A full example
A pair of headphones has an MRP of ₹2,000 and is on sale with 40% off, plus an extra 10% off, and you have a ₹100 coupon:
- 40% off ₹2,000 → ₹1,200.
- Extra 10% off ₹1,200 → ₹1,080.
- ₹100 coupon → ₹980.
Total saving ₹1,020, or a 51% total discount. If the headphones usually sell for ₹1,400, the real saving compared with the normal price is ₹420 – still a good deal, but a very different number from "40% + 10% + coupon".
Quick checklist before you buy
- Calculate the final price, not the advertised percentages.
- Compare with the usual price and with at least one other store.
- Add delivery, convenience or platform fees.
- Read bank offer caps, minimum amounts and card types.
- For "No Cost EMI", check whether a processing fee applies.
- Ask yourself: would I buy this at this price without the sale banner?
Working out a quick percentage? The percentage calculator can tell you instantly how much cheaper one price is than another.
Frequently asked questions
Is 50% + 20% off the same as 70% off?
No. The 20% applies to the already-discounted price, so the total discount is 60%.
What discount is Buy 2 Get 1 Free?
If all items cost the same, it is about 33% off each item, because you pay for two out of three.
How do I calculate stacked discounts?
Multiply the remaining fractions: for 30% and then 10%, 0.7 × 0.9 = 0.63, so you pay 63% of the price – a 37% total discount.
Is cashback the same as a discount?
Not exactly. A discount lowers the price you pay now. Cashback is returned later, sometimes with conditions or as points, so it's worth slightly less than the same instant discount.