Discount calculator
Enter the price and the discount: the sale price and your savings appear. An item at 80 with 30% off costs 56, saving 24.
- Checked on thousands of cases
- Updated November 7, 2026
Sale price
You save 24.00
Quick challenge
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Test yourself: every answer is computed by the tool, and the wrong choices are the most common traps.
How it works
Formula: Sale price = price × (1 − discount/100)
A 30% discount leaves 70% of the price: sale price = price × (1 − 30/100). Two discounts in a row multiply instead of adding up: 20% off then 10% off gives 0.8 × 0.9 = 0.72, so 28% off, not 30%. To find the original price, divide the sale price by the share that is left: 45 ÷ 0.75 = 60.
Worked examples
80.00 with 30% off
Sale price: 56.00, saving 24.00.
100 with 20% off, then an extra 10% off
Final price: 72.00. The total discount is 28%, not 30%.
Original price of an item at 45 after 25% off
45 ÷ 0.75 = 60.00.
Common mistakes
Adding two discounts: 20% + 10% = 30%.
They multiply: 0.8 × 0.9 = 0.72, so 28% off.
Finding the original price by adding 25% to the sale price: 56.25.
Divide by the share that is left (0.75): 60.00.
Mixing up “50% off the second item” and “50% off everything”.
For 2 items at 40.00, you pay 60.00 instead of 80.00: only 25% off.
What the calculation leaves out
- The tool works on the price you enter. Where sales tax is added at the register, it comes on top, on the sale price.
- Amounts are not rounded the way a register does: a store may round cents differently.
Sale price of an item at 100.00
| Discount | Sale price | Savings |
|---|---|---|
| 10 % | 90.00 | 10.00 |
| 15 % | 85.00 | 15.00 |
| 20 % | 80.00 | 20.00 |
| 25 % | 75.00 | 25.00 |
| 30 % | 70.00 | 30.00 |
| 40 % | 60.00 | 40.00 |
| 50 % | 50.00 | 50.00 |
| 60 % | 40.00 | 60.00 |
| 70 % | 30.00 | 70.00 |
Frequently asked questions
How do I work out 30% off?
Multiply the price by 0.7: 80 × 0.7 = 56. You save 80 × 0.3 = 24.
Do two 20% discounts make 40% off?
No: 0.8 × 0.8 = 0.64, so 36% off in total.
How do I find the price before the sale?
Divide the sale price by (1 − discount): an item at 45 after 25% off cost 45 ÷ 0.75 = 60.