In short: A discount calculator finds the sale price and savings from a percentage off: price × (1 − discount ÷ 100), so 25% off $80 is $60.
About Discount Calculator
“30% off, plus an extra 10% at checkout” sounds like 40% off. It is actually 37%, because the second discount applies to the already-reduced price. This calculator does the arithmetic for single and stacked discounts and shows exactly how much you save.
Add a sales tax rate to see the price you will actually pay at the register — in the United States, sales tax is usually added after discounts. All numbers update as you type, so you can quickly compare two deals.
How to use Discount Calculator
- Enter the original price.
- Enter the discount percentage, and an extra discount if the deal stacks.
- Optionally add your local sales tax rate.
- Read the final price, the amount saved and the effective total discount.
Examples
120 with 30% off then an extra 10%: 120 × 0.70 × 0.90 = 75.60. You save 44.40, an effective 37% discount.
The same 75.60 with 8% tax costs 81.65 at checkout.
Frequently asked questions
Do two discounts add up?
No, they multiply. 30% then 10% equals 1 − 0.7 × 0.9 = 37% total, not 40%.
Does the order of stacked discounts matter?
No. 10% then 30% gives the same result as 30% then 10%.
How do I find the original price from a sale price?
Divide the sale price by (1 − discount). A 75 item after 25% off was 75 ÷ 0.75 = 100.
Is tax applied before or after the discount?
In most places tax is charged on the discounted price, which is what this calculator assumes.
Updated November 2026 · Free, no signup · How we build and test tools