Discount Calculator

See what you pay after a discount and how much you save, or work back from a sale price to the original price.

You save

$20.00

Before discount

Price after discount

$60.00

Original price

$80.00

Please note: This is an example calculation, not financial advice. Personal circumstances, changes in rules and rates, and additional costs are not included. If in doubt, talk to a financial adviser.

How this number is calculated

The blocks use your input. Change a value above and they update with it.

Step 1 · Discount as a decimal

Discount (%)25 ÷ Per100 =Discount as a decimal0.25

Step 2 · Share you pay

1 − Discount as a decimal0.25 =Share you pay0.75

Step 3 · Original price

(This price is: Before discount) Price$80.00 =Original price$80.00

Step 4 · Price after discount

(This price is: Before discount) Original price$80.00 × Share you pay0.75 =Price after discount$60.00

Step 5 · Discount amount

Original price$80.00 × Discount as a decimal0.25 =Discount amount$20.00

How the calculation works

This calculator shows what something costs after a discount and how much you save. If you only know the sale price, it works back to the original price.

The discount amount is the original price times the discount percentage, divided by 100. The price after discount is the original price times the share you pay: 1 minus the discount as a decimal. Working back goes the other way: the original price is the price after discount divided by that share. With a 100% discount the price after discount is always 0, so there is nothing to work back from and the calculator shows 0 as the original price. All amounts are rounded to the nearest cent, with half a cent rounded up.

Formula

Discount = original price × discount ÷ 100. Price after discount = original price × (1 − discount ÷ 100). Working back: original price = price after discount ÷ (1 − discount ÷ 100).

Assumptions

One discount applies, as a percentage of the whole price.
Shipping, deposits and other extra costs are not included.
All amounts are rounded to the nearest cent, with half a cent rounded up.
With a 100% discount there is nothing to work back from, so the calculator shows 0 as the original price.

Example calculations

The button fills in the calculator above, so you can carry on from there.

Winter coat in the sale

You save
$39.00

Price $129.99 · Before discount · Discount (%) 30
Money off the groceries

You save
$8.64

Price $86.40 · Before discount · Discount (%) 10
Back to the original price

You save
$10.50

Price $59.50 · After discount · Discount (%) 15

Frequently asked questions

How do I calculate 20% off a price?

Multiply the price by 0.20 to get the discount, or by 0.80 to get what you pay. 20% off 50 is a discount of 10, so you pay 40.

How do I find the original price before a discount?

Divide the sale price by 1 minus the discount as a decimal. If something costs 60 after 25% off, the original price was 60 ÷ 0.75 = 80. Adding 25% to 60 gives 75, which is wrong.

Is 20% off twice the same as 40% off?

No. The second discount comes off the price that is already reduced. 20% off 100 is 80, and another 20% off that is 64. Together that is 36% off, not 40%.

How do I work out the discount percentage from two prices?

Divide the difference between the old and the new price by the old price and multiply by 100. From 80 down to 60 is 20 ÷ 80 × 100 = 25% off.

How much is 'buy one, get one half price' as a discount?

If both items cost the same, you pay 1.5 times the price for 2 items: 25% off the total. 'Buy one, get one free' works out at 50% off.

Is the discount taken off before or after tax?

Where prices include VAT, as in the UK and the EU, the discount comes off the price including VAT and the VAT goes down in proportion. Where sales tax is added at the checkout, as in the US, it is usually worked out on the price after the discount, although some coupons are an exception.

Last reviewed: 4 October 2026