How it works
The price is multiplied by 1 minus the discount expressed as a decimal, so a 25% discount multiplies by 0.75. The amount saved is the difference between the original and sale price.
Take 249.99 with 15% off. Divide the percentage by 100 to get 0.15, which is the share of the price being taken away. One minus that share, 1 − 0.15 = 0.85, is the share being kept. Multiplying, 249.99 × 0.85 = 212.4915. The saving is then the removed share, 249.99 − 212.4915 = 37.4985. The guide to percentages covers the underlying rule.
The multiplication is the same as the Percentage Decrease Calculator, which leaves the percentage unrestricted, and the mirror image of the Percentage Increase Calculator, which multiplies by 1 plus the percentage as a decimal. What this page adds is the limit: 0 to 100% is the full span of a reduction, so anything outside that range is a different calculation rather than a larger discount.
Formula: Sale price = price × (1 − discount ÷ 100)
Examples
A quarter off
80 with a 25% discount has a sale price of 80 × 0.75 = 60, saving 20.
A discount on a price with pence
249.99 with a 15% discount keeps 85% of the price, so the sale price is 249.99 × 0.85 = 212.4915 and the saving is 37.4985. Neither figure is rounded to a whole number of pence.
A full discount
45 with a 100% discount multiplies by 1 − 1 = 0, so the sale price is 0 and the saving is the whole 45. A zero sale price is a valid result, not an error, and 100% is the largest discount accepted.
Common uses
- Checking what a "was and now" price saves against the original ticket price
- Taking a percentage off a quote or an order where the reduction was agreed as a percentage rather than a cash amount
- Confirming that a percentage discount and a fixed cash reduction come to the same figure on a given price
- Turning a percentage-off voucher into the cash amount it removes from a basket total
Things to keep in mind
- The discount percentage must be between 0 and 100. A discount cannot exceed the full price, and a negative discount is a markup, not a discount — see the Markup Calculator for that.
- The price cannot be negative.
- Each discount is taken on the price at that moment, so two successive 15% discounts on 249.99 give 249.99 × 0.85 × 0.85 = 180.617775, not the 174.993 that a single 30% discount would produce.
- One discount is applied to one price. The calculator does not stack several codes, exclude an item from a total, or add tax, postage or a currency conversion to the result.
- Results are kept to 12 significant digits and displayed to up to 10 decimal places, so a sale price such as 212.4915 is shown in full rather than being rounded to 2 decimal places. Round it yourself if you need a whole-penny or whole-cent amount.