About the Discount Calculator
Know the real sale price before you reach the register. Enter the original price and discount — plus an optional stacked "extra % off" coupon — to see the final price and total savings.
Runs in your browser, instantly, with no upload — useful when you are standing in a shop working out whether a sale is actually a sale.
Results are estimates for general information only and are not financial advice. Actual loan terms, returns, and taxes vary — confirm figures with your lender or advisor.
How to use it
- Enter the original price.
- Enter the discount percentage.
- Read the final price and the amount saved.
Stacked discounts do not add up
'30% off, then an extra 20% off' is not 50% off. The second discount applies to the already-reduced price, not the original.
The real combined discount is 1 − (0.70 × 0.80) = 44%. Retailers are not being dishonest — but the arithmetic reliably works in their favor.
A worked example
An item at $129.99:
- 35% off → $84.49, saving $45.50
- 30% off then 20% off → $72.79, an effective 44% discount
- A genuine 50% off would be $65.00
The stacked offer sounds like the biggest of the three and is actually worth less than a straight half-price cut.
Common mistakes
- Adding stacked percentages together. Multiply the remainders instead.
- Comparing a discount to an inflated 'was' price that the item never genuinely sold at.
- Forgetting sales tax, which is applied after the discount and changes the amount you actually hand over.
Questions people ask
How do I work out the original price from a sale price?
Divide by (1 − the discount). An item at $84.49 after 35% off was $84.49 ÷ 0.65 = $129.99.
Does the order of stacked discounts matter?
No. 30% then 20% gives exactly the same result as 20% then 30% — multiplication is commutative.
What about a coupon that takes a fixed amount off?
Apply percentage discounts first, then subtract the fixed amount, unless the terms specify otherwise.