“30% off” signs are easy to read and surprisingly easy to misjudge, especially when a second coupon is stacked on top. This calculator gives the exact price you pay, the dollars you save and the true combined percentage, and can add sales tax so you see the number that will show up at the register.
How to use the discount calculator
- Enter the original price.
- Enter the discount and choose % off or $ off.
- If there is a second promotion — an extra percentage at checkout or a coupon — enter it in extra discount (stacked). Leave it blank otherwise.
- Optionally enter your sales tax rate to see the final total.
- Read the price and savings on the tape, with a table of the same item at other common discounts.
Discount formulas
Worked example
A jacket costs $80. It is marked 25% off, and you have a coupon for an extra 10% off at checkout.
First discount = 80 × 25% = $20 → $60.00
Extra discount = 60 × 10% = $6 → $54.00
You save 80 − 54 = $26.00, which is 26 ÷ 80 = 32.5% — not 35%
With 8% sales tax: 54 × 0.08 = $4.32, so the register total is $58.32
Common discounts on a $100 item
| Discount | You save | You pay |
|---|---|---|
| 10% off | $10 | $90 |
| 20% off | $20 | $80 |
| 25% off | $25 | $75 |
| 30% off | $30 | $70 |
| 40% off | $40 | $60 |
| 50% off | $50 | $50 |
| 25% + extra 20% | $40 | $60 |
| 50% + extra 20% | $60 | $40 |
Comparing offers
Percent off vs. dollars off
A $15-off coupon beats 15% off on anything under $100 and loses on anything over $100. The break-even price is the dollar amount divided by the percentage: $15 ÷ 0.15 = $100.
Buy-one-get-one deals
“Buy one, get one 50% off” on two equal items is a 25% discount on the pair. “Buy one, get one free” is 50% off — but only if you wanted two.
Mental math shortcuts
- 10% off: move the decimal one place left and subtract.
- 25% off: take a quarter off — the price becomes three-quarters.
- 33% off: take a third off — the price becomes two-thirds.
- Stacked: multiply the “you pay” fractions, not the discounts: 0.75 × 0.9 = 0.675 of the price.
If you already know the sale price and want the original, or the percentage off, use the sale price calculator. For a multi-item order with a discount, shipping and tax, use the sales calculator.
Results are estimates rounded to the cent. Store policies on coupons, stacking and taxable amounts vary.
Frequently asked questions
How do I calculate a percentage discount?
Multiply the original price by the discount as a decimal to get the amount off, then subtract it. For 25% off $80: 80 × 0.25 = $20 off, so you pay $60. Equivalently, multiply the price by 1 − 0.25 = 0.75.
Is 25% off plus an extra 10% off the same as 35% off?
No. The extra 10% comes off the already-reduced price. On $80, 25% off gives $60 and another 10% off gives $54 — a combined discount of 32.5%, not 35%. The combined rate is 1 − (0.75 × 0.90).
Does the order of stacked discounts matter?
For two percentage discounts, no: 25% then 10% gives the same price as 10% then 25%. When one discount is a fixed dollar amount, order matters — taking $10 off before a percentage discount saves less than taking it off after.
Is sales tax charged on the original or discounted price?
Store discounts reduce the taxable price in every US state, so tax is charged on the discounted amount. Some states tax the pre-coupon price when a manufacturer reimburses the store for the coupon.