How to use the discount calculator
Enter the original price and the discount percentage. If a second discount applies — an extra percentage off at checkout, a coupon on top of a sale price, a loyalty or employee discount — enter it as the additional discount. The calculator applies it to the already-reduced price, the way stores do, and shows the final price, your savings and the true combined discount.
Discount formulas
Sale price = original price × (1 − discount ÷ 100)
Two discounts = original price × (1 − d1 ÷ 100) × (1 − d2 ÷ 100)
Combined discount = 1 − (1 − d1) × (1 − d2), using decimals
Why 20% off plus 10% off is not 30% off
The second discount is taken from the reduced price, not the original. On an $80 item, 20% off brings the price to $64. The extra 10% is 10% of $64 — $6.40, not $8 — so you pay $57.60. You saved $22.40, which is 28% of $80. The missing 2 points are the 10% you would have saved on the $16 that was already gone.
The order of two percentage discounts does not matter: 10% then 20% gives 80 × 0.9 × 0.8, the same $57.60, because multiplication works in any order.
Stacked discounts at a glance
| Discounts | Combined discount | You pay on a $100 item |
|---|---|---|
| 20% + 10% | 28% | $72.00 |
| 25% + 10% | 32.5% | $67.50 |
| 30% + 20% | 44% | $56.00 |
| 40% + 20% | 52% | $48.00 |
| 50% + 20% | 60% | $40.00 |
| 50% + 50% | 75% | $25.00 |
| 60% + 15% | 66% | $34.00 |
Notice that 50% plus 50% is 75% off, not free.
Dollar-off coupons change the math
When one discount is a fixed dollar amount, order does matter. On a $100 item with $20 off and 25% off: taking the $20 first gives (100 − 20) × 0.75 = $60, while taking 25% first gives 100 × 0.75 − 20 = $55. If the terms let you choose, apply the percentage first.
Smart shopping tips
- Compare final prices, not percentages. 40% off a $150 list price ($90) is worse than 25% off the same item listed at $110 elsewhere ($82.50).
- Work back to the original price by dividing the sale price by (1 − discount). A $63 price after 30% off was 63 ÷ 0.70 = $90.
- Remember tax. Sales tax is usually charged on the discounted price; add it with the sales tax calculator.
- Read "up to" carefully. "Up to 70% off" means some items reach 70%; the one you want may be far less.
Frequently asked questions
How do I calculate a discount?
Multiply the price by the discount as a decimal to get the savings, then subtract. 30% off $50: 50 × 0.30 = $15 off, so you pay $35. Or multiply by (1 − 0.30) directly: 50 × 0.70 = $35.
How do I combine two discounts?
Multiply the remaining fractions: (1 − d1) × (1 − d2). For 25% and then 10% off, 0.75 × 0.90 = 0.675, so you pay 67.5% of the price — a 32.5% combined discount.
How do I find the discount percentage from two prices?
Subtract the sale price from the original, divide by the original and multiply by 100. $80 marked down to $60 is (80 − 60) ÷ 80 × 100 = 25% off. The percentage calculator handles any percentage change.
Is buy one, get one free the same as 50% off?
Only if you want two items of the same price. Buy one, get one 50% off works out to 25% off the pair.
Does the order of percentage discounts matter?
No. Two percentage discounts give the same final price in either order. Order only matters when one of them is a fixed dollar amount.
Last updated: October 8, 2026