The discount formula
Amount saved = original price × (discount % ÷ 100)Sale price = original price − amount savedEquivalently, the sale price is the original price multiplied by what is left: at 25% off you pay 75%, so sale price = price × 0.75. Both routes give the same answer — use whichever is quicker on paper.
Worked example
A jacket at $120 with 25% off: you save 120 × 0.25 = $30 and pay $90. If your state adds 8% sales tax, the tax is charged on the discounted $90 (not the original $120), adding $7.20 — a true final price of $97.20. Enter 8 in the tax field above to see that step.
Stacked discounts do not add
"Extra 20% off the sale price" on top of 25% off is not 45% off. The second discount applies to what remains: $120 → $90 after 25% off → $72 after a further 20% off. That is a total saving of $48, which is 40% off, not 45%. Whenever discounts stack, apply them one at a time, in order.
Percent off vs percentage points
A discount is a percentage of the price. It is different from a price falling "by 25 percentage points," a phrase used for rates (like interest) rather than prices. If a store advertises both, this calculator follows the price meaning: percent off the amount you would have paid.
Frequently asked questions
How do I calculate 20% off a price in my head?
Find 10% (move the decimal one place left), then double it. For $120: 10% is $12, so 20% is $24 off and the sale price is $96. For 25%, halve the price and halve it again — a quarter off.
Is tax calculated before or after a discount?
In most US states, sales tax is charged on the discounted price when the discount is the store's own. Manufacturer coupons are an exception in some states, where tax may be charged on the full price. The calculator follows the common store-discount rule.
What does 'up to 70% off' mean?
It means the largest discount in the store is 70%, not that everything is 70% off. Check the specific item's tag and run its real percentage here before assuming the headline figure applies.
How do I find the original price from a sale price?
Divide the sale price by what remains: if you paid $72 after 20% off, the original was 72 ÷ 0.80 = $90. This is called a reverse percentage.