Work out a sale two ways: a percent off the original price, or a fixed dollar amount off. Enter any two of the original price, the discount, and the sale price (plus the amount saved in percent-off mode) to solve the rest.
Stacked discounts: why 25% + 20% is 40%
Successive discounts use different bases. On a $120 item, 25% off leaves $90. The additional 20% is then $18 off that $90 balance, leaving $72. The total saving is $48, or 40% of the original price.
price paid = $120 × (1 − 0.25) × (1 − 0.20) = $72
combined discount = 1 − (0.75 × 0.80) = 0.40 = 40%
Adding the labels would suggest 45% off and a $66 price, which is $6 lower than the actual stacked result. This example assumes the offer terms allow the discounts to be combined.
Percentage saved and percentage points
To find the percentage saved, use the original price as the denominator. A price change from $80 to $60 saves $20, and $20 ÷ $80 × 100 = 25%. Enter the original and sale prices in the Percent off tab to reproduce it.
A change in a discount rate from 20% to 25% is an increase of 5 percentage points. Relative to the old 20% rate, it is a 25% increase in the rate: (25 − 20) ÷ 20 × 100. Those descriptions answer different questions.
Common markdowns
| Off | You pay | You save on $59.99 |
|---|---|---|
| 10% | 90% of list | $6.00 |
| 15% | 85% of list | $9.00 |
| 20% | 80% of list | $12.00 |
| 25% | 75% of list | $15.00 |
| 50% | half of list | $30.00 |
Examples
15% off $59.99
A $59.99 item at 15% off is $50.99 after the discount, and you save $9.00.
$17.50 off $100
A $17.50 coupon on a $100 item brings the price to $82.50, which is 17.5% off.
Half of three cents
50% of $0.03 is $0.015. Rounded independently, the sale price is $0.02 and the savings are $0.02.
Formula
Percent off scales with the original price. Fixed amount off subtracts a coupon. Each displayed money value is rounded to the nearest cent from the raw (unrounded) figure — the sale price is not the original minus the already-rounded savings.
sale price (percent off) = original × (1 − discount% ÷ 100)
amount saved = original × (discount% ÷ 100)
sale price (amount off) = original − discount amount
discount % = discount amount ÷ original × 100
combined discount % = [1 − (1 − first rate) × (1 − second rate)] × 100
Compare the final cost
This calculator evaluates the numbers you enter; it does not add sales tax, shipping, membership charges, or other required fees. The US Federal Trade Commission recommends including delivery and add-on costs when comparing an online purchase and reviewing coupon terms before buying. It also cautions that an advertised percentage may be measured from a suggested retail price that is higher than the price commonly charged. Compare final prices across sellers rather than relying on the markdown label alone.
Sources: FTC online shopping security tips and FTC guidance on advertised sale discounts.
Add tax and compare the final price
After calculating a discount, use the Sales Tax Calculator to apply the relevant taxable amount and rate. For a VAT-inclusive price, use the VAT Calculator to separate net price and tax. Coupon terms and local tax rules determine which price is taxable.