Discount Calculator
Turn a percent off into the sale price and the amount you actually save.
You save $20.00 (25% off).
To find a sale price, multiply the original by (1 − percent ÷ 100). For 25% off $80: $80 × (1 − 25 ÷ 100) = $80 × 0.75 = $60. The amount saved is the difference, $80 − $60 = $20, which equals $80 × 25 ÷ 100.
Sale price and amount saved
A discount is a percent taken off the original price. Convert that percent to a multiplier — 25% off leaves 75%, or 0.75 — and multiply the original by it to get the price you pay. The amount saved is whatever you do not pay: the original minus the sale price, which is the same as the original times the percent over 100.
amount saved = original − sale price = original × % ÷ 100
Worked example
A $80 jacket is marked 25% off. What do you pay, and how much do you save?
- 1 Turn the percent into a multiplier. 1 − 25 ÷ 100 = 0.75 — you pay 75% of the price.
- 2 Multiply the original price. $80 × 0.75 = $60. That is the sale price you pay.
- 3 Subtract to find the saving. $80 − $60 = $20 saved, equal to $80 × 25 ÷ 100.
Percent off as a multiplier
Multiply the original price by the multiplier to get what you pay.
| Percent off | Multiplier | $100 becomes |
|---|---|---|
| 10% | 0.90 | $90.00 |
| 20% | 0.80 | $80.00 |
| 25% | 0.75 | $75.00 |
| 33% | 0.67 | $67.00 |
| 50% | 0.50 | $50.00 |
| 70% | 0.30 | $30.00 |
Stacked discounts multiply — they don’t add
When two discounts apply one after another, you can’t just add the percents. The second percent is taken off the already-reduced price, so the multipliers multiply. 20% off then 10% off is 0.80 × 0.90 = 0.72, an effective 28% off — not 30%. The order doesn’t change the result, but the total saving is always a little less than the sum suggests.