How to calculate a discount
To find a sale price, turn the percentage off into a multiplier and apply it to the original price:
Sale price = Original price × (1 − Discount ÷ 100) and Savings = Original price − Sale price
Example: a $80 jacket at 25% off → 80 × 0.75 = $60. You save $20.
Quick mental shortcuts
| Discount | Shortcut | On $80 |
|---|---|---|
| 10% off | Move the decimal one place, subtract | 80 − 8 = $72 |
| 20% off | Double the 10%, subtract | 80 − 16 = $64 |
| 25% off | Divide by 4, subtract | 80 − 20 = $60 |
| 50% off | Halve it | $40 |
Stacked (double) discounts
When a store offers “an extra 10% off sale prices”, the second discount applies to the already reduced price. 20% then 10% off = 0.8 × 0.9 = 0.72, which is a 28% total discount, not 30%. The calculator shows the combined discount for you.
Find the discount percentage
If you know both prices, the discount is (original − sale) ÷ original × 100. A $120 item on sale for $90 is (120 − 90) ÷ 120 × 100 = 25% off. For price rises rather than cuts, use the percentage increase calculator.
Discount table: common sale percentages
| Original price | 10% off | 20% off | 25% off | 30% off | 50% off |
|---|---|---|---|---|---|
| $20 | $18.00 | $16.00 | $15.00 | $14.00 | $10.00 |
| $50 | $45.00 | $40.00 | $37.50 | $35.00 | $25.00 |
| $100 | $90.00 | $80.00 | $75.00 | $70.00 | $50.00 |
| $250 | $225.00 | $200.00 | $187.50 | $175.00 | $125.00 |
Percent off versus amount off
A coupon worth a fixed amount (for example $15 off) is better than a percentage when the price is low; a percentage is better when the price is high. $15 off beats 10% off on anything under $150, and 10% off wins above that. Work out both with the calculator before choosing.
Is a “buy one, get one 50% off” deal a good discount?
Buying two items at $40 with the second at half price costs $60 instead of $80: a 25% discount on the pair. It is only a saving if you needed two. Compare it with a straight percentage by entering $80 as the original price and $60 as the sale price in the “Find Discount %” tab.
To see how a price has changed over time rather than on sale, use the percentage increase calculator; for invoices with a discount line, try the invoice generator.