Discount Calculator: Sale Price and Savings
A discount calculator finds how much you save and what you pay when a percentage is taken off an original price. Enter the price and discount rate to calculate the sale price. If you want to add tax, enter a tax percentage; this calculation applies it after the discount.
How to calculate a discount and sale price
Convert the discount percentage to a decimal by dividing it by 100. Multiply the original price by that decimal to find the amount saved. Subtract the savings from the original price to find the discounted price.
Savings = original price × discount ÷ 100
Sale price = original price × (1 − discount ÷ 100)
For a 20% discount, you save one fifth of the price and pay the remaining 80%. A 0% discount leaves the price unchanged. A 100% discount reduces the discounted price to zero.
Discount calculation examples
20% off 100: savings are 100 × 20 ÷ 100 = 20. The sale price is 100 − 20 = 80.
25% off 80: savings are 20 and the sale price is 60. 15% off 49.99: the unrounded savings are 7.4985 and the sale price is 42.4915. With a two-decimal currency display, those amounts appear as 7.50 and 42.49.
Keep the percentage separate from the amount saved. “20% off” and “20 off” produce the same savings only when the original price is 100.
How to add tax after a discount
This calculator uses the discounted price as the tax base. Multiply that price by the entered tax percentage, then add the tax amount to find the final price.
Tax amount = sale price × tax rate ÷ 100
Final price = sale price + tax amount
For an original price of 100, a 20% discount, and an entered tax rate of 10%, the sale price is 80, the tax amount is 8, and the final price is 88. Savings before tax remain 20.
The rate is supplied by you. This page does not determine which tax rate or tax treatment applies to a purchase. If the original price already includes tax and no additional tax should be added, use 0 in the tax field. It does not extract tax from a tax-inclusive price.
How to find the discount percentage from two prices
If you know the original price and sale price before added tax, divide their difference by the original price and multiply by 100.
Discount percentage = (original price − sale price) ÷ original price × 100
For a price reduced from 120 to 90, the savings are 30. Dividing 30 by 120 and multiplying by 100 gives a 25% discount. This reverse formula requires an original price greater than zero.
Do successive discounts add together?
Usually, successive percentage discounts are applied one after another to the remaining price. A 20% discount followed by another 10% discount gives a combined discount of 28%, rather than 30%: 100 becomes 80, then 72.
Combined discount = [1 − (1 − first rate ÷ 100) × (1 − second rate ÷ 100)] × 100
This calculator accepts one discount percentage. For successive discounts, calculate the combined rate first and enter that rate, or calculate each step separately.
Frequently asked questions
Can I enter decimal percentages?
Yes. A discount such as 12.5% is valid. Both discount and tax rates must be from 0% to 100%.
Does changing the currency convert the price?
No. It changes the currency used to label and format your entered amounts. It does not use exchange rates.
Why might displayed amounts differ by a small rounding amount?
The calculation keeps unrounded intermediate values and formats each displayed amount separately. Shops may round discounts or tax at different stages. Japanese yen is displayed without decimal places, while the other listed currencies use two.
Can the original price be zero?
Yes. The discount, tax, and final price are all zero. Negative original prices are not supported.
Does the savings figure include tax?
No. It is the discount on the original price before tax. The separate tax amount is added to the discounted price.