How to Calculate a Discount and Sale Price
A discount is a percentage taken off a price. Whether you are checking a sale, pricing a promotion, or stacking two offers, the maths is a short calculation - but stacked discounts and reverse calculations trip people up.
Sale price after a discount
Example: 80 with 25% off. 80 x (1 - 0.25) = 80 x 0.75 = 60. You can also find the saving directly: 80 x 0.25 = 20 off, so the price is 80 - 20 = 60. Both routes give the same answer.
How much you save
The saving is simply the discount percentage of the original price. On 80 at 25%, you save 20. On a 1,200 quote at 10%, you save 120.
Stacked discounts do not add up
Two discounts of 20% and 10% are not 30% off. They apply one after the other: 100 less 20% is 80, then less 10% is 72 - a 28% total discount, not 30%. The second discount is taken off the already-reduced price, so stacked offers are always worth slightly less than the sum suggests.
Reverse: find the original price
If something is 60 after 25% off, the original was 60 / 0.75 = 80. Do not add 25% to 60 - that gives 75, which is wrong, because the 25% was taken off the larger original, not the smaller sale price.
Discounts and your profit
From a seller's side, a discount comes straight off your margin. If a product costs you 60 and sells for 100, you make 40. A 20% discount drops the price to 80, so your profit falls to 20 - a 20% price cut halved the profit. Always check what a promotion does to margin before running it.
Use the Discount Calculator
The Discount Calculator shows the final price and the amount saved, and supports a second stacked discount so you can see the true combined saving rather than guessing. Enter the price and percentage and read both numbers at once.
Frequently asked questions
How do I calculate percent off in my head?
Find 10% (move the decimal one place left), then scale. For 30% off 50: 10% is 5, so 30% is 15 off, leaving 35. For 25%, take a quarter. These shortcuts cover most shop discounts without a calculator.
Is a bigger percentage always the better deal?
Not necessarily - it depends on the starting price. 50% off an overpriced item can still cost more than 20% off a fairly priced one. Compare the final prices, not the discount percentages.
Use the tools
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