Discount Calculator
Find the sale price and amount saved — including a second, stacked discount if there is one.
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How to work out a discount
- Enter the original price.
- Enter the discount percentage, and an extra discount if there’s a second one.
- Read the sale price and how much you save.
The formula
A single discount: sale price = price × (1 − rate ÷ 100). A second "extra" discount is applied to the already-discounted price, not the original — this is how "25% off, then an extra 10% off" actually works at checkout, and it's why two discounts never simply add together: 25% + 10% off stacked comes out to a 32.5% effective discount, not 35%.
Nothing entered here is sent to a server — the entire calculation runs as JavaScript in your browser tab.
Questions about discounts
How do I calculate a discount?
Multiply the price by the discount as a decimal and subtract it. 30% off £80 is £80 × 0.3 = £24 off, so you pay £56.
Is 25% off plus an extra 10% off the same as 35% off?
No. The extra 10% comes off the already reduced price, so together they make 32.5% off, not 35%.
How do I find the original price from a sale price?
Use the reverse percentage calculator: £60 after 25% off was £60 ÷ 0.75 = £80.
How do I work out a discount in my head?
Find 10% by moving the decimal point one place left, then multiply. 20% off £45 is 2 × £4.50 = £9 off.