Everyday formula
Discount Formula
Learn how to calculate discount amount, sale price and percent off from an original price.
Formula
Sale price = original price × (1 − discount ÷ 100)What the formula means.
Convert the discount percentage to a decimal, subtract it from one, then multiply by the original price. The discount amount is original price minus sale price.
The discount is applied to the original price.
Multiple sequential discounts are not simply added together.
Taxes may be calculated before or after discounts depending on local rules.
Variables.
POriginal price
Price before the discount.
dDiscount rate
Percent off expressed as a decimal inside the formula.
SSale price
Price after applying the discount.
Worked example.
25% off $120
- 25% = 0.25
- 1 − 0.25 = 0.75
- $120 × 0.75 = $90
Try your own numbersDiscount Calculator
↗Common mistakes.
- Subtracting 25 dollars when the offer is 25 percent.
- Adding sequential discount percentages as though they share the same base.
- Rounding before the final price is calculated.
Quick questions.
How do I find the amount saved?
Multiply original price by the discount rate, or subtract sale price from original price.
Is 20% off then 10% off the same as 30% off?
No. The second discount is applied to the already-discounted price, producing a 28% total reduction.