PercentSwift

Discount calculator

Enter the original price and the percentage off. Add an extra discount if a coupon applies on top of a sale. The second tab works out the percentage off from a was-and-now price.

Sale price after a discount

Settings
$
%
%

Optional. For a coupon applied after the first discount.

Sale price

$60.00

$80.00 with 25% off is $60.00. You save $20.00.

You save
$20.00

Formula

Sale price = Price × (1 − Discount ÷ 100)

Steps

  1. Take 25% off $80.00: $80.00 × (1 − 25 ÷ 100) = $60.00
  2. You save $80.00 − $60.00 = $20.00

Exact decimal arithmetic, calculated in your browser.

Examples

Each one loads into the calculator above.

How to calculate a sale price

Multiply the original price by 1 minus the discount as a decimal. For 25% off $80, that’s 80 × 0.75 = $60, and you save $20. You can also find the saving first (25% of 80 = 20) and subtract it.

Stacked discounts

When a coupon applies to an already-reduced price, the discounts multiply. 20% off and then a further 10% off a $100 item is 100 × 0.8 × 0.9 = $72, which is 28% off in total, not 30%. The order doesn’t change the answer: 10% then 20% also ends at $72.

Finding the percentage off

Divide the saving by the original price. A tag showing $60 crossed out and $45 underneath is a $15 saving, and 15 ÷ 60 = 25% off. Dividing by the sale price instead ($15 ÷ $45 = 33%) overstates the discount.

Rounding

Prices are shown rounded to the cent, but the saving is calculated from the rounded sale price, so the two figures always add up to the original price. A store that rounds differently may be a cent off.

Limits

Discounts are capped at 100%. Above that the store would be paying you, so the calculator asks you to check the entry. For a price that went up, use the percentage increase calculator.

Questions people ask

Guides that use this calculator