How to Calculate a Discount

A "25% off" sign is easy to read and surprisingly easy to get wrong in your head. Here's the simple formula for the final price and the amount you save — plus quick shortcuts and how to handle stacked discounts.

The percent-off formula

Two small steps give you everything:

Worked example: a $80 item at 25% off. Amount saved = 80 × 0.25 = $20. Final price = 80 − 20 = $60.

You can also get the final price in one step by multiplying by what's left: 80 × (1 − 0.25) = 80 × 0.75 = $60.

Quick mental-math shortcuts

• 10% — move the decimal one place: 10% of $80 is $8.
• 20% — 10% doubled: $16.
• 25% — a quarter: divide by 4.
• 50% — half.
• 15% — 10% plus half of that (10% + 5%).

Stacked discounts aren't additive

A "50% off, then an extra 20% off" deal is not 70% off. The second discount applies to the already-reduced price. On $80: 50% off gives $40, then 20% off that gives $32 — an effective 60% off, not 70%. Always apply discounts one after another.

Working out the original price

If you know the sale price and the percent off, you can find the original: divide the sale price by what's left. A $60 item that was 25% off means 60 ÷ 0.75 = $80 originally.

Step by step

1. Open the Discount Calculator.
2. Enter the original price.
3. Enter the discount percentage.
4. Read the final price and the amount you save instantly.

FAQ

Does this include sales tax?
The discount is calculated on the price you enter. If tax is added at checkout, it's usually applied after the discount — enter the pre-tax price for the discount, then add tax separately.

How do I calculate the percent off from two prices?
Divide the amount saved by the original price. Saving $20 on an $80 item is 20 ÷ 80 = 25% off.

Can I stack two coupons here?
Apply them one at a time: calculate the first discount, then run the result through again with the second percentage.

Are my numbers sent anywhere?
No. The calculation runs entirely in your browser. Nothing you type is uploaded.