This free discount calculator does the sale-price maths for you. Type in the original price and the percentage off, and it shows the final price you pay plus the amount you save - updating as you type. You can stack a second discount (handy for "extra 10% off already-reduced lines"), or flip to the second mode to work out what percentage discount two prices actually represent.
How to work out a discount
A percentage discount is just a slice taken off the original price. There are two easy ways to do it by hand:
- Find the amount off, then subtract. Multiply the price by the discount percentage divided by 100, then take that away from the price. For 25% off £80: 80 × 0.25 = £20 off, so you pay £80 − £20 = £60.
- The shortcut. Multiply the price by (100 − discount) ÷ 100 to get the final price in one step. For 25% off £80: 80 × 0.75 = £60. Same answer, fewer steps.
To go the other way and work out the percentage off from two prices, take the amount saved, divide it by the original price, and multiply by 100. From £80 down to £60 that is 20 ÷ 80 × 100 = 25%.
A worked example - stacking two discounts
Say a jacket is £80, marked "25% off, plus an extra 10% off at the till". Stacked discounts are applied one after another - the second comes off the already-reduced price, so it is not the same as 35% off:
| Original price | £80.00 |
| Less 25% | − £20.00 |
| Sub-total | £60.00 |
| Less a further 10% (of £60) | − £6.00 |
| Final price you pay | £54.00 |
Total saved: £26.00, which is 32.5% off the original - not 35%. A single 35% discount would have saved £28.00, so stacked percentages are always worth a little less than the same figures added together. The calculator above handles all of this instantly.
Using it as a sale price calculator
Most people reach for a percent off calculator in the shop or at the checkout, when the ticket says something like "30% off" and they want the real price before they commit. That is exactly what this sale price calculator is for: type the price, type the percentage, and read off what you actually pay. No mental arithmetic, no rounding mistakes.
It works both ways round. As a percentage discount calculator it takes a price and a percent off and shows the sale price. Flip to the second mode and it becomes the reverse - hand it the original price and the price you paid, and it tells you the percentage discount you were given. Handy for checking whether a "half price" label is really 50% off, or working out how good a clearance deal actually is.
Frequently asked questions
How do I calculate a discount?
Multiply the original price by the discount percentage divided by 100 to get the amount off, then subtract that from the price. For example, 25% off £80 is 80 × 0.25 = £20 off, leaving £60. Or take the shortcut: multiply the price by (100 − discount) ÷ 100, so 80 × 0.75 = £60.
How do I work out the sale price after a percent off?
Multiply the original price by (100 − the percent off) ÷ 100. For 30% off £50, that is 50 × 0.70 = £35. The percentage discount calculator above shows this the moment you type the two figures in, so you can use it as a quick sale price calculator while you shop.
How do I work out the percentage discount from two prices?
Subtract the sale price from the original price, divide the result by the original price, then multiply by 100. An item reduced from £80 to £60 is a £20 saving; 20 ÷ 80 = 0.25, which is 25% off. The "Find the % off" mode above does this for you.
How do two stacked discounts work?
Stacked discounts are applied one after another, not added together. A 25% discount followed by a further 10% off is not 35% off. The second discount comes off the already-reduced price: £80 less 25% is £60, then less a further 10% is £54 - a total saving of £26, or 32.5% off.
Does a bigger single discount beat two smaller stacked ones?
Usually, yes. Two stacked discounts are worth less than adding the percentages together. A single 35% off £80 saves £28, but 25% then a further 10% saves only £26. The order of two stacked discounts does not change the final price, but a single combined percentage always saves more.
How do I add VAT or find the price before a discount?
This tool works on the price as shown. If VAT is already in the ticket price, the discount comes off the VAT-inclusive figure, which is normal for UK retail. To find the original price before a known discount, divide the sale price by (100 − discount) ÷ 100 - a £60 sale price at 25% off was originally 60 ÷ 0.75 = £80.
Is this discount calculator free to use?
Yes. It is completely free, needs no sign-up, and runs entirely in your browser, so your numbers never leave your device. DigiSurf Agency builds it as one of a set of free tools for UK shoppers and business owners.
