Discount Percentage Calculator
What's the discount? (two prices → % off)
What's the final price? (price + % off)
How to use the discount percentage calculator
- Know both prices? Use the left panel: enter original and sale price to get the exact discount percentage and dollar savings.
- Know the percent off? Use the right panel: enter the original price and the discount % to get the final price.
- Stacked discounts: run the right panel twice — apply the first discount, then use the result as the new original price. 20% + 10% is 28% total, never 30%.
- With tax: discounts apply before sales tax in nearly all US states — calculate the discounted price here, then add your local tax rate.
Discount math, both directions
Every discount question is one of two: "what percent off is this?" (two prices, find the rate) or "what will I pay?" (price and rate, find the total). This calculator does both side by side — no switching modes, no formula lookup. Type, read, done.
The formulas
Discount % = (original − sale) ÷ original × 100. A $80 item at $60 is 25% off. Final price = original × (1 − discount%). A $120 item at 25% off is $90. The mirror-image trap: 25% off then 25% back on does not return to the original — $120 → $90 → $112.50, because the percentage bases differ.
Stacked discounts never add
"Extra 10% off already-reduced items" applies to the reduced price. 20% + 10% = 28% total; 50% + 30% = 65%, not 80%. Retailers rely on shoppers adding the numbers. To stack: multiply the remainders — (1−0.20) × (1−0.10) = 0.72, so 28% off.
For sellers: discount vs. margin
A 20% discount usually costs far more than 20% of profit. Selling at $100 with a 40% margin, a 20% discount cuts profit in half — you need 50% more volume just to stay even. Before a sale, check the real cost against your bulk discount tiers or run your margins in the wholesale price calculator. Setting prices from cost? Use the contractor markup calculator or the 40% markup shortcut.
Frequently Asked Questions
How do I calculate a discount percentage?
(Original price − sale price) ÷ original price × 100. From $80 to $60 is (80−60)/80 = 25% off.
How much is 25% off $120?
$30 off, final price $90. Multiply the price by (1 − 0.25) = 0.75.
Do stacked discounts add together?
No — each applies to the already-reduced price. 20% + 10% = 28% total. Multiply the remainders: 0.80 × 0.90 = 0.72.
Is a discount applied before or after sales tax?
Before, in nearly all US jurisdictions — you pay tax on the discounted price. Coupons funded by the manufacturer can differ in some states.