Discount Calculator
Find the sale price and how much you save, including stacked discounts like “an extra 10% off” and sales tax.
About the Discount Calculator
A percent-off discount takes that share of the original price away. Stacked discounts are applied one after another, not added together: 30% off and then an extra 20% off is 44% off in total, not 50%.
Where tax is added at the till, it's charged on the discounted price, so a discount also lowers the tax you pay.
The formula
Sale price = Price × (1 − d₁) × (1 − d₂)
- d₁
- first discount as a decimal (25% = 0.25)
- d₂
- any extra discount on the reduced price
Total discount = 1 − (1 − d₁)(1 − d₂). You save = Price − Sale price.
Stacked discounts: the real total
| Offer | Looks like | Actually |
|---|---|---|
| 20% + extra 10% | 30% | 28% |
| 30% + extra 20% | 50% | 44% |
| 40% + extra 25% | 65% | 55% |
| 50% + extra 50% | 100% | 75% |
How to read your result
- Sale price is what you pay before any tax.
- You save is the money off the original price.
- Total discount shows the combined percentage of stacked offers.
Worked example
A ₹2,000 jacket at 30% off, then an extra 20% off
- After 30%: 2,000 × 0.70 = ₹1,400
- After extra 20%: 1,400 × 0.80 = ₹1,120
- You save ₹880, which is 44%
Questions people ask
How do I work out a percentage off quickly?
For 10% off, move the decimal point one place left and subtract. For 25%, divide by 4. For 20%, divide by 5.
Does the order of two discounts matter?
No. 30% then 20% gives the same price as 20% then 30%, because multiplication works in any order.