Discount Calculator
See the sale price and how much you save.
Good to know. 30% off, then an extra 20% off, is 44% off, not 50%. Shops know this.
How it works
In plain words
Multiply the price by what is left after each discount. A 30% discount leaves 70%, so multiply by 0.7. An extra 10% leaves 90% of that, so multiply by 0.9 as well.
The formula
sale price = price × (1 − d ÷ 100) × (1 − extra ÷ 100) you save = price − sale price
Worked example
A 30% discount on a price of 80: 80 × 0.7 = 56.00, so you save 24.00.
Sources
No outside data or rates: this is plain arithmetic.
7 automated tests check its answers on every change.
About the discount calculator
Shops love percentages because they sound bigger than they are, and they get confusing fast once discounts are stacked. This calculator gives you the actual price at the till.
The key to discounts is to think about what you pay, not what you save. With 30% off, you pay 70% of the price. That turns the calculation into a single multiplication: 80 × 0.7 = 56.
Stacked discounts are where people get caught out. "30% off, plus an extra 20% off the sale price" is not 50% off. The second discount applies to the already reduced price, so you pay 0.7 × 0.8 = 0.56 of the original. That is a 44% discount in total. Enter the second discount in the "extra" field to see the real total.
Before you celebrate, check the original price is real. A discount from an inflated "was" price is not much of a saving. If you know the sale price and the discount and want to find the original price, use the reverse percentage calculator.
Sales tax is not included. If your country adds tax at the till, apply it to the final price afterwards.
Questions people ask
How do I calculate 30% off?
Multiply the price by 0.7. For 80 that is 56, a saving of 24.
Is 30% off plus an extra 20% off the same as 50% off?
No. The second discount applies to the reduced price, so you pay 0.7 × 0.8 = 56% of the price, a total discount of 44%.
Does the order of stacked discounts matter?
No. Multiplication works in any order, so 20% then 30% gives the same price as 30% then 20%.
How do I find the original price from a sale price?
Divide the sale price by what was left after the discount. 56 after 30% off: 56 ÷ 0.7 = 80. The reverse percentage calculator does this for you.