How to calculate a discount
Sale price = original price × (1 − discount ÷ 100)
A $80 item at 25% off: 80 × 0.75 = $60. You save 80 − 60 = $20.
Stacked discounts are not added together
“25% off, plus an extra 10% at checkout” is applied one after the other: 80 × 0.75 × 0.90 = $54. That is 32.5% off in total, not 35%. Fill in the “extra % off” box to see the combined discount.
Sales tax comes after the discount
In most US states, sales tax is charged on the discounted price. $60 with 7% tax is 60 × 1.07 = $64.20. Coupons that the store pays for usually reduce the taxable price; manufacturer coupons sometimes don’t. Check your state’s rule if the exact cents matter.
Quick discount math
| % off | Multiply the price by | $50 becomes |
|---|---|---|
| 10% | 0.90 | $45.00 |
| 20% | 0.80 | $40.00 |
| 25% | 0.75 | $37.50 |
| 30% | 0.70 | $35.00 |
| 40% | 0.60 | $30.00 |
| 50% | 0.50 | $25.00 |
| 70% | 0.30 | $15.00 |
Stacked discounts don’t add up
“20% off, then an extra 10% off” is not 30% off. The second discount applies to the already reduced price: $100 → $80 → $72, a total of 28% off. Multiply the prices you keep: 0.80 × 0.90 = 0.72.
Sales tax comes after the discount
In the US, sales tax is charged on the discounted price. A $60 item at 25% off with 8% tax costs $60 × 0.75 = $45, then $45 × 1.08 = $48.60.
Related calculators
- Percentage Calculator: X% of Y, X is what % of Y, and more.
- Percent Change Calculator: Percentage increase, decrease and difference.
- Margin & Markup Calculator: Profit margin, markup and selling price.
Questions people ask
How do I find the percent off from two prices?
Subtract the sale price from the original, divide by the original, and multiply by 100. $80 down to $60 is 20 ÷ 80 = 25% off. The percent change calculator does this too.
How do I find the original price before a discount?
Divide the sale price by (1 − discount). If $60 is the price after 25% off, the original was 60 ÷ 0.75 = $80.
Formula checked October 2026 · How we calculate