How do I calculate a percentage discount?

Multiply the price by the discount as a decimal to get the saving, then subtract it. For 30% off 80, 80 × 0.30 = 24, so the price is 56.

How do I work out the discount from two prices?

Subtract the sale price from the original, divide by the original and multiply by 100.

Do two discounts add up?

No. The second applies to the reduced price, so 20% then 10% off is a 28% total discount.

Does the calculator include sales tax?

No. Apply your local rate to the final price if the displayed prices exclude tax.

Discount Calculator

Work out the sale price, the amount saved and the effective discount when offers stack.

Updated September 19, 2026Checked by the editorial team

Original price

Currency symbol

Discount

Extra discount (optional)

Another (optional)

Final price

$90.00

You save: $30.00
Effective discount: 25%

Type in a price and a discount percentage and see the final price and the money saved. Add a second discount, such as an extra 10% at the till, and the calculator shows the true combined discount.

If you already know the original and the sale price, switch the mode and it will tell you what percentage you were given.

How discount calculator works

Each discount is applied one after another to the price left by the previous one. That is how retailers apply “extra 10% off sale prices”, and it means two discounts never simply add up.

Use the currency symbol selector if you want figures shown in your currency. Tax is not included, so add it afterwards if your prices exclude it.

The formula

Sale price  =  Original × (1 − D1 ÷ 100) × (1 − D2 ÷ 100)
Discount given  =  (Original − Sale) ÷ Original × 100

Worked example: 35% off 89.99, and a stacked offer

35% off 89.99: 89.99 × 0.65 = 58.49, which saves 31.50.

Stacked: 25% off 200 leaves 150, and a further 10% off leaves 135.

That is 65 saved, an effective discount of 32.5%, not 35%.

When to use this tool

Checking whether a sale really saves as much as the banner says.
Comparing two offers, such as 30% off versus 20% off plus a further 10%.
Working out the percentage off when a shop only shows old and new prices.
Budgeting for a planned purchase.

Common mistakes to avoid

Adding stacked discounts. 20% off and then 10% off is 28%, not 30%.
Calculating the discount on the sale price instead of the original.
Forgetting tax or delivery, which can change which offer is actually cheaper.

Frequently asked questions

How do I calculate a percentage discount?: Multiply the price by the discount as a decimal to get the saving, then subtract it. For 30% off 80, 80 × 0.30 = 24, so the price is 56.
How do I work out the discount from two prices?: Subtract the sale price from the original, divide by the original and multiply by 100.
Do two discounts add up?: No. The second applies to the reduced price, so 20% then 10% off is a 28% total discount.
Does the calculator include sales tax?: No. Apply your local rate to the final price if the displayed prices exclude tax.

Learn more

Results are for information only and are not financial, legal or medical advice. The calculation logic is covered by automated tests, and examples on this page are worked out and re-checked before publishing. Spotted a mistake? Tell us.