Discount Calculator
Sale price and savings.
Discount Calculator at a glance
Discount Calculator is a free online calculator you can use right now to sale price and savings โ no account, no install and no usage limit. It runs entirely inside your browser, so whatever you enter stays on your own device.
- Price
- Free โ no trial, no paid tier, no watermark
- Sign-up
- Not required
- Where it runs
- In your browser โ nothing is uploaded to a server
- Works on
- Chrome, Safari, Firefox and Edge โ desktop, tablet and phone
- Category
- Calculators
About Discount Calculator
Enter an original price and a discount percentage to get the final price and the amount saved.
The arithmetic people most often get wrong is stacked discounts. Two successive 20% reductions are not 40% off โ the second applies to the already-reduced price, so ยฃ100 becomes ยฃ80 and then ยฃ64, an effective discount of 36%. The same logic makes '50% off, then an extra 20% off' equal 60% off rather than 70%. Retailers rely on this reading better than it calculates.
Percentage increase and decrease are similarly asymmetric, and the mistake is common enough to be worth stating. A price that rises 20% and then falls 20% does not return to where it started: ยฃ100 becomes ยฃ120, then ยฃ96. The reduction is applied to a larger base than the increase was, so you end up below the original.
For comparing offers, convert everything to a unit price. 'Buy one get one free' is 50% off if you want two and nothing at all if you want one. '3 for 2' is a 33% discount at three units. A percentage off a higher starting price can easily be worse value than a smaller percentage off a lower one, which is what makes headline discount figures unreliable on their own.
How to use Discount Calculator
- Enter the original price.
- Enter the discount percentage, or the sale price to find the percentage.
- Read the final price and the amount saved.
Frequently asked questions
Do two 20% discounts make 40% off?
No. The second applies to the already-reduced price, so 100 becomes 80 and then 64 โ an effective 36% off. Stacked discounts always total less than their sum.
If a price rises 20% then falls 20%, is it back to the start?
No, it ends 4% lower. 100 rises to 120, and 20% of 120 is 24, leaving 96. The decrease is calculated on a larger base than the increase was.
How do I compare 'buy one get one free' with a percentage off?
Convert both to a unit price. BOGOF is 50% off if you want two units and no discount at all if you want one. '3 for 2' is a 33% discount at three units. Comparing headline percentages alone is misleading.
How do I find the discount percentage from two prices?
Subtract the sale price from the original, divide by the original, and multiply by 100. Entering both prices here does it for you.