Discount Calculator
Enter the price and discount — add a stacked second discount or sales tax if you have them. Results update as you type.
How this calculator works
The final price is original × (1 − d₁/100) × (1 − d₂/100), then × (1 + tax/100) if you add sales tax. The key subtlety is that stacked discounts multiply: the second percentage comes off the already-reduced price, so "25% off plus an extra 20% off" is never 45% off. Savings compare the pre-tax discounted price to the original, and the effective discount turns the whole stack into one honest percentage.
Worked example
A $120 jacket at 25% off costs $90 — you save $30. Now stack an extra 20% off coupon: the 20% applies to $90, not $120, giving a final price of $72. Total saved is $48, an effective discount of 40% — not the 45% the two labels suggest. Add 8% sales tax to the single-discount case and the register shows $97.20, because tax is charged on the $90 you actually pay.
Frequently asked questions
How do stacked discounts combine?
They multiply, not add. Each discount applies to the price left after the previous one, so 25% off followed by 20% off is 0.75 × 0.80 = 0.60 of the original price — a 40% effective discount, not 45%. The second coupon works on a smaller number, which is why stacked deals always total a bit less than the sum of their labels.
Is sales tax applied before or after the discount?
In most US states, tax is charged on the amount you actually pay — the discounted price — so this calculator applies tax after the discounts. Rules can differ for manufacturer coupons and rebates in some states, where tax is sometimes computed on the pre-coupon price, so check your receipt if the pennies matter.
How do I work backwards from a sale price to the original?
Divide instead of multiplying. If an item costs $90 after 25% off, the original was 90 ÷ (1 − 0.25) = 90 ÷ 0.75 = $120. A common mistake is adding 25% back to $90, which gives $112.50 — wrong, because the 25% was taken from the larger original price, not from the sale price.
Is a percent-off deal better than a dollar-off deal?
Convert them to the same units and compare. $30 off a $120 item equals 25% off; on a $60 item the same $30 coupon is a much stronger 50% off. Percent-off deals scale with price — better on expensive items — while fixed dollar amounts hit hardest on cheap ones.