Money
Discount Calculator
Use this discount calculator to see the sale price after a percentage off, how much you save, or what percentage discount you're actually getting.
It also handles the “extra 10% off” situation, where a second discount is taken off the already-reduced price, and it can work backwards from a sale price to the original price.
Calculator
Fill in the boxes above and your answer appears here.
Worked examples
Real numbers, worked out by the same calculator. Press “Use these numbers” to try one above.
30% off £200
- Sale price
- £140.00
- You save
- £60.00
30% off £200.00 is £140.00, saving you £60.00.
20% off £100, then a further 10% off
- Sale price
- £72.00
- You save
- £28.00
- Total discount
- 28%
20% off, then a further 10% off, takes £100.00 down to £72.00. That's 28% off in total, not 30%.
Was £80, now £60
- Discount
- 25%
- You save
- £20.00
Going from £80.00 to £60.00 is a 25% discount.
How discounts are calculated
Sale price = original price × (1 − discount). 30% off £200 is £200 × 0.7 = £140, so you save £60.
Discount percentage = (original − sale) ÷ original × 100. Was £80, now £60: a £20 saving on £80 is 25%.
Original price = sale price ÷ (1 − discount). If £75 is the price after 25% off, the original was £75 ÷ 0.75 = £100.
Two discounts don't add up
“20% off, then an extra 10% off” is not 30% off. The second discount applies to the already-reduced price. £100 becomes £80, and 10% off £80 is £72, so the total discount is 28%. The more discounts you stack, the further the total falls short of simply adding them.
Discounts and VAT
Because VAT is a fixed percentage of the net price, a percentage discount gives the same result whether you take it off the price before VAT or the price including VAT. 20% off £120 (including VAT) is £96, which is exactly the same as 20% off £100 plus VAT.
Frequently asked questions
How do I calculate 20% off?
Multiply the price by 0.8. For 30% off, multiply by 0.7. For any discount, multiply by 1 minus the discount as a decimal.
How do I work out the discount percentage from two prices?
Subtract the sale price from the original, divide by the original price, and multiply by 100. Was £80, now £60 is 20 ÷ 80 = 25% off.
Are two discounts added together?
No. They multiply. 20% off followed by 10% off is 28% off in total, not 30%.
How do I find the original price after a discount?
Divide the sale price by 1 minus the discount as a decimal. If £75 is 25% off, the original was 75 ÷ 0.75 = £100. Don't add 25% to £75: that gives £93.75.
Does the discount come off before or after VAT?
A percentage discount gives the same result either way, because VAT is also a percentage. A fixed amount discount, such as £10 off, does differ.
Related tools
- Everyday calculationsPercentage CalculatorFind a percentage of a number, work out what percentage one number is of another, add or take off a percentage, or find the whole from a part.
- Everyday calculationsPercentage Change CalculatorWork out the percentage increase or decrease between two numbers, and see what change you'd need to get back to where you started.
- MoneyVAT CalculatorAdd VAT to a price or find the VAT inside a price that already includes it. Choose 20%, 5% or 0%, or type your own rate. Free and instant.
Formulas tested against hand-worked answers. Last reviewed 29 September 2026. These calculators do arithmetic only; they are not financial, tax or legal advice.