Discount Calculator
Work out a sale price, stack several discounts correctly, find the percentage off from two prices, or recover the original price.
You pay
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Enter a price and a discount.
Working backwards
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All Calculators tools →This tool runs entirely in your browser. Nothing you enter is sent to our servers, so there is nothing for us to store or see.
About the Discount Calculator
Work out what something actually costs after a discount — one discount or several, as a percentage or a fixed amount, with or without tax.
Stacked discounts do not add up. "30% off, then take a further 20% off at the till" is 44% off, not 50%, because the second discount applies to what is left after the first: £100 becomes £70, then £56. That gap is 6% of the original price, and it is the single most common misreading of a sale sign. Every step is shown so you can see where the money goes.
Two reverse calculations are included, because they are what people are usually standing in a shop trying to do. What percentage off is this? — from the original and the sale price. And what was it before? — from the sale price and the advertised percentage, which is how you check whether a "was £80" claim is plausible.
Where tax lands matters only when the discount is a fixed amount: £10 off before tax and £10 off after tax give different totals, while a percentage gives the same answer either way. The switch is there for the first case and the tool says so rather than pretending it always matters.
How to use the Discount Calculator
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Enter the original price
Any currency — the arithmetic is the same. Thousands separators are accepted.
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Enter the discount
As a percentage, or switch to a fixed amount off. A fixed discount larger than the price is rejected rather than producing a negative total.
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Add any further discounts
Each extra percentage applies to what is left after the previous one. The step-by-step breakdown shows the running price after each.
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Add tax if it applies
Choose whether the discount comes off before or after tax. With a percentage discount both give the same total; with a fixed amount they do not.
Frequently asked questions
Is 30% off plus an extra 20% the same as 50% off?
No. The second discount applies to the already-reduced price, so £100 goes to £70 and then to £56 — an effective 44% off, not 50%. The two are only equal if both discounts are applied to the original price, which shops almost never do. On a £100 item the difference is £6.
How do I work out what percentage off something is?
Subtract the sale price from the original, divide by the original, and multiply by 100. From £80 to £52 is £28 off, and 28 ÷ 80 × 100 is 35%. The reverse panel does this for you — and doing it the other way round, dividing by the sale price, is a common error that inflates the discount.
How do I find the original price from a sale price?
Divide the sale price by one minus the discount as a decimal. A £52 item at 35% off was £52 ÷ 0.65 = £80. Do not add 35% to £52 — that gives £70.20, because the percentage was of the higher number. This is the same arithmetic mistake as removing tax by subtraction.
Does the discount come off before or after tax?
It depends on the jurisdiction and the retailer, and it only changes the total when the discount is a fixed amount. £10 off a £100 net price plus 20% tax gives £108; 20% tax first and then £10 off the £120 gross gives £110. A percentage discount produces the same total whichever order you use.
Are my figures sent anywhere?
No. Everything is calculated in your browser and nothing is transmitted or stored — which also means the tool works with no signal, which is exactly when you want it in a shop.