Discount / Sale Price Calculator
Calculate a sale's final price and amount saved from one discount, or two stacked discounts.
How to use the Discount Calculator
- Enter the original, pre-sale price.
- Enter the discount percentage.
- If a second discount stacks on top (for example an extra 10% off at checkout), tick "Add a second, stacked discount" and enter it.
- Read the final price and how much you save in total.
About the Discount Calculator
A discount calculator applies a percentage off an original price and shows the final price along with exactly how much you save, without doing the percentage math by hand at checkout. Enter the original price and a discount percentage, and it instantly returns the discounted price.
It also handles stacked discounts — a common source of confusion, like 'an extra 10% off already-discounted items.' Two stacked discounts don't add together the way people often assume: 20% off followed by 10% off the reduced price is not the same as 30% off, because the second discount applies to a smaller, already-discounted amount. This calculator applies discounts multiplicatively, showing the intermediate price after the first discount so the difference is easy to see.
Worked example
Example: an $80 item with a 25% discount comes to a final price of $60.00, saving $20.00. Stacked example: a $100 item with 20% off, then an extra 10% off that reduced price, comes to an intermediate price of $80.00 after the first discount, then a final price of $72.00 — not $70.00, which is what a simple (incorrect) 30%-off calculation would suggest.
Working backwards from a sale price
To find the original price from a sale price, divide by (1 − discount). An item selling for $45 after 25% off was originally $45 ÷ 0.75 = $60. Subtracting 25% from the sale price instead gives $33.75, which is wrong because the discount was taken from the larger original price. The same reasoning shows how much stacked discounts really save: 20% off and then another 10% off is 1 − (0.8 × 0.9) = 28% in total, not 30%.
When the order of discounts matters
Two percentage discounts give the same result in either order, but mixing a percentage with a fixed-amount coupon doesn't. On a $100 item, taking $10 off and then 20% leaves $72, while taking 20% first and then $10 off leaves $70. Stores usually decide the order, but when you can choose, apply the percentage first so it works on the larger amount — the fixed coupon is worth the same either way.
Decoding common deals
- Buy one, get one 50% off: if you're buying two anyway, that's 25% off each.
- Buy two, get one free: 33.3% off each of the three items, but only if you wanted three.
- 'Up to 70% off': the headline percentage applies to a few items; check the discount on the ones you actually want.
- Sales tax is usually charged on the discounted price, so the saving on the receipt total is the discount plus the tax you no longer pay on it.
- Compare price per unit (per 100 g, per item), not the discount percentage, when package sizes differ.
Frequently asked questions
- Is 20% off plus 10% off the same as 30% off?
- No. Stacked discounts apply one after another to a shrinking amount, not added together. $100 with 20% off then 10% off comes to $72.00, while a flat 30% off the original $100 would be $70.00 — stacked discounts are always slightly less generous than adding the percentages suggests.
- How do I calculate the discount percentage from an original and sale price?
- Subtract the sale price from the original price, divide by the original price, and multiply by 100. This calculator works in the other direction (price and percentage in, sale price out), but the percentage-calculator tool's percentage-decrease mode solves this exact reverse question.
- Why does the order of two stacked discounts not matter?
- Because both discounts are multiplied together with the original price (price × (1 − d1) × (1 − d2)), and multiplication is commutative — applying the 20% discount first and then 10% gives the exact same final price as applying 10% first and then 20%.
- Does this work for calculating a discount in any currency?
- Yes — the calculation is currency-agnostic. Enter the original price in whatever currency you're working with, and the final price and savings will be in that same currency, since the math is a pure percentage calculation.