How do I apply two discounts one after the other?

Apply them in sequence, not by adding them. 20% off then 10% off is not 30% off: it leaves you paying 0.8 × 0.9 = 0.72, so 28% off. Run this calculator twice, using the first result as the second price.

Does the discount apply before or after sales tax?

In the United States, the discount is applied first and sales tax is charged on the reduced price. Enter the pre-tax price here, then add tax to the result.

How do I find the original price from the sale price?

Divide the sale price by 1 minus the discount as a decimal. A $187.49 item after 25% off started at 187.49 ÷ 0.75 = $249.99.

Money

Discount Calculator

Enter the original price and the discount to see the sale price and the saving.

The formula

saving = price × discount ÷ 100

sale price = price − saving

Worked example

A $249.99 tool at 25% off

249.99 × 0.25 = 62.50 saved
249.99 − 62.50 = 187.49 to pay

Where this goes wrong

Adding stacked discounts together

An extra 20% off an item already reduced by 30% is not 50% off. The second discount applies to the already-reduced price: $100 becomes $70, then $56 — a real saving of 44%. Stacked percentages multiply, and they always come out smaller than their sum.

Questions

How do I apply two discounts one after the other?: Apply them in sequence, not by adding them. 20% off then 10% off is not 30% off: it leaves you paying 0.8 × 0.9 = 0.72, so 28% off. Run this calculator twice, using the first result as the second price.
Does the discount apply before or after sales tax?: In the United States, the discount is applied first and sales tax is charged on the reduced price. Enter the pre-tax price here, then add tax to the result.
How do I find the original price from the sale price?: Divide the sale price by 1 minus the discount as a decimal. A $187.49 item after 25% off started at 187.49 ÷ 0.75 = $249.99.