Discount Calculator
Find the sale price and how much you save — including stacked discounts.
How to use this calculator
Enter the original price and the discount percentage, then press Calculate sale price. The tool shows the final price and the amount you save. If a sale stacks two discounts — say an item is already reduced and then there is an extra "20% off at the till" — enter the second percentage in the optional box and the tool applies them in sequence. It is built for shopping: working out whether a deal is as good as it sounds before you reach the checkout.
The formula explained
A discount reduces the price by a percentage of itself:
sale price = price × (1 − d₁ ÷ 100) × (1 − d₂ ÷ 100)
Converting each discount to a decimal and subtracting from one gives the fraction of the price you still pay. Multiplying the original price by that fraction gives the sale price; the difference is your saving. The key thing with two discounts is that they multiply rather than add — the second discount applies to the already-reduced price, which is why stacked deals save a little less than the percentages added together would suggest.
A worked example
An item priced $80 with 25% off costs 80 × 0.75 = $60, saving $20. Add a second 10% off and the price becomes 60 × 0.90 = $54 — a total saving of $26, which is 32.5% off, not 35%. The calculator does this stacking for you.
Frequently asked questions
How do you calculate a discount?
Multiply the price by the discount percentage divided by 100 for the amount off, then subtract it from the price.
How do you find the sale price?
Multiply the price by one minus the discount written as a decimal.
How do two discounts stack?
They apply in sequence and multiply, so 20% then 10% is 28% off, not 30%.