Quick answer: multiply the price by (1 − discount ÷ 100). 30% off 2,500 is 2,500 × 0.70 = 1,750, a saving of 750. An extra 10% is taken from the new price, not the original: 1,750 × 0.90 = 1,575 – a total discount of 37%, not 40%.
Why 30% + 10% isn’t 40% off
Stacked discounts are applied one after the other. The second percentage is taken from an already-reduced price, so it saves less than it seems. That’s why “extra 20% off sale items” often sounds better than it is.
| Discounts | Real total discount |
|---|---|
| 30% then 10% | 37% |
| 50% then 20% | 60% |
| 20% then 20% | 36% |
| 70% then 10% | 73% |
Quick ways to check a sale tag
- 10% off: move the decimal one place and subtract (2,500 → 250 off).
- 25% off: subtract a quarter. 50% off: halve it.
- “Buy one, get one half price” on two equal items is 25% off each.
- “3 for 2” is a third off – 33.3% – but only if you wanted three.
Discount first, then tax
In most countries sales tax or VAT is charged on the price you actually pay, so it is applied after the discount. If a shelf price already includes VAT (as in the UK, EU and Pakistan’s retail prices), leave the tax box empty – the discount already reduces the VAT too.
Running the shop rather than shopping? The profit margin calculator checks that a sale price still leaves you a profit, and the percentage calculator works out any percentage change between two prices.
How to calculate a discount
- Enter the original price. Use the price before any reduction.
- Enter the discount. Type it or tap a quick value. Add a second discount if there is an “extra % off”.
- Add quantity and tax if needed. Both are optional; tax is added after the discount.
- Read the final price. See what you pay and what you save, in money and as a real percentage.
Worked example: which deal is better?
Three shirts at 1,200 each. Offer A: 25% off everything. Offer B: buy 2, get 1 free.
| Offer | You pay | Real discount |
|---|---|---|
| 25% off | 2,700 | 25% |
| Buy 2 get 1 free | 2,400 | 33.3% |
Offer B wins – but only if you want all three shirts. If you only need two, 25% off saves 600 while “buy 2 get 1” saves nothing.
Common mistakes
- Adding stacked discounts (30% + 20% is 44% off, not 50%).
- Comparing “up to 70% off” signs – only a few items usually carry the top discount.
- Forgetting delivery fees that cancel an online discount.
Frequently asked questions
How do I calculate 30% off a price?
Multiply the price by 0.70. For 2,500 that is 1,750, a saving of 750.
How do two discounts add up?
They multiply: (1 − 0.30) × (1 − 0.10) = 0.63, so you pay 63% of the price – a 37% total discount.
How do I find the original price from a sale price?
Divide the sale price by (1 − discount). If 1,750 is 30% off, the original was 1,750 ÷ 0.70 = 2,500.
What percentage discount did I get?
Divide the saving by the original price and multiply by 100. Saving 600 on 2,000 is a 30% discount.
Is tax charged before or after the discount?
Usually after: you pay tax on the discounted price. Coupons from manufacturers can be treated differently in some US states.
Does the calculator round prices?
It shows prices to two decimal places in your chosen currency, which is how most tills round.
How do I calculate the original price before a discount?
Divide the sale price by (1 − discount). 1,750 after 30% off was 1,750 ÷ 0.7 = 2,500.
Is 40% off better than “buy one get one 50% off”?
Buy one, get one half price on two equal items is 25% off overall, so 40% off is better.