Discount Calculator
See the final price and how much you save from a percentage off, or work backwards: the discount between two prices, or the price before a sale. Stacked offers show what they really come to.
Runs in your browser. Your data is not uploaded.How our tools work
Taken off the already reduced price.
How do I calculate a discount?
Multiply the price by the discount percentage and divide by 100 to get the saving, then subtract it: 20% off 100 saves 20, so you pay 80. It also works backwards: 60 marked down to 42 is 30% off, and 72 after 20% off was originally 90, because you divide by 0.80.
- Choose what to work out: the sale price, the discount percentage, or the original price.
- Enter the two numbers you know. For a sale price you can add an extra discount, such as a coupon, which comes off the already reduced price.
- Read the result with its working, the amount saved and both prices.
Need to work backwards from a sale price, or compare a percentage with a fixed amount off? Read our guide: Discount Maths: Stacked Discounts, Working Backwards and Tax
Formulas & Methods
Sale price
Example: 100 × (1 − 0.20) = 80
Two discounts in a row
Example: 100 × 0.80 × 0.90 = 72, a total of 28% off
Discount from two prices
Example: (60 − 42) ÷ 60 × 100 = 30%
Original price
Example: 72 ÷ 0.80 = 90
Key features
Three directions
Find the sale price, the percentage off between two prices, or the price before a discount.
Stacked discounts
Add an extra discount to see the real total when a coupon comes on top of a sale.
Working shown
Each result shows the sum with your numbers, so you can check it on a receipt.
Why 20% plus 10% off isn’t 30% off
A second discount is taken off the already reduced price, not the original. 20% off 100 gives 80, and 10% off 80 is 8, so the final price is 72: 28% off in total, not 30%. The same mistake runs the other way: to undo 20% off, divide by 0.80. Adding 20% back to a sale price of 72 gives 86.40, but the original was 90.
A fixed amount off or a percentage off?
Compare them at your price. A percentage grows with the price and a fixed amount doesn’t, so they break even where the percentage equals the amount: 10 off and 15% off are worth the same at 10 ÷ 0.15 = 66.67. Below that the fixed 10 saves more (15% of 50 is only 7.50); above it the percentage wins (15% of 100 is 15).
Tax changes the comparison only for the fixed amount. A percentage discount and a percentage tax give the same total in either order: 10% off 100 with 20% tax is 108 whether the tax is added first or last. A fixed 10 off before 20% tax gives 108, but taken off the total after tax it gives 110, because the tax was charged on the 10 as well.
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Frequently Asked Questions
How do I find the discount percentage from a receipt?
Choose “Discount %”, then enter the price before and after the discount. A shirt marked down from 60 to 42 was 30% off: 18 saved, divided by the original 60. Check the receipt’s prices are both before tax or both after it.
Is 20% off plus an extra 10% off the same as 30% off?
No. The extra 10% is taken from the reduced price, so the total is 28% off. The more discounts are stacked, the bigger the gap.
Does the result include sales tax or VAT?
No. The calculator works on the prices you enter. To add VAT or sales tax to the final price, use the Tax Calculator.
Why can’t I work back from a 100% discount?
Because the sale price is 0 whatever the original was, so there is nothing to divide. Any discount below 100% can be undone.
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Related guides & tutorials
Discount Maths: Stacked Discounts, Working Backwards and Tax
Work out a sale price and the amount saved, find a discount percentage from two prices, undo a discount, and see why stacked discounts don’t add up.
Profit Margin vs Markup: How to Calculate Both
Profit margin and markup explained with worked examples: gross, operating and net margin, converting markup to margin, and pricing for a target margin.