Sale tags usually show two of three numbers: the original price, the sale price and the percentage off. This calculator fills in the missing one, so you can check a “was/now” tag, work out what an item cost before a promotion, or see how deep a markdown really is.
How to use the sale price calculator
- Choose what to solve for: the sale price, the original price or the percent off.
- Enter the two values that appear.
- Read the answer on the tape, along with the amount saved and the share of the original price you pay. When you know the original price, a table shows it at other discounts.
Sale price formulas
All three are the same relationship rearranged. The key idea is that the percentage is always measured against the original price.
Worked examples
Sale price. A $120 item at 30% off: 120 × 0.70 = $84.00, saving $36.
Original price. A tag says $84 after 30% off: 84 ÷ 0.70 = $120.00.
Percent off. The price dropped from $120 to $84: (120 − 84) ÷ 120 = 0.30 = 30% off.
Original prices for a $50 sale price
| Advertised discount | Original price |
|---|---|
| 10% off | $55.56 |
| 20% off | $62.50 |
| 25% off | $66.67 |
| 30% off | $71.43 |
| 40% off | $83.33 |
| 50% off | $100.00 |
| 60% off | $125.00 |
| 75% off | $200.00 |
Notice how quickly the original price climbs as the discount deepens: at 75% off you are paying a quarter of the original, so the original is four times the sale price.
Reading sale tags critically
Compare-at prices
“Compare at” or “list” prices are reference prices chosen by the seller. The Federal Trade Commission’s guides on deceptive pricing say a former price should be one at which the item was actually offered in good faith for a reasonable period. A large percentage off an inflated list price is not a real saving.
Rounded percentages
Tags often round: “save 35%” on a $79.99 item marked down to $51.99 is really 35.0% off, but “save 33%” on $59.99 to $39.99 is 33.3%. The calculator shows the exact figure to two decimal places.
Discounts on discounts
When a second percentage applies at the register, the combined discount is less than the sum of the two. Use the discount calculator to stack promotions correctly and add sales tax. Retail buyers planning price cuts on whole lines of stock can use the markdown calculator, which also shows the effect on margin.
Results are estimates rounded to the cent and don't include sales tax.
Frequently asked questions
How do I find the original price from a sale price?
Divide the sale price by 1 minus the discount as a decimal. If an item is $84 after 30% off, the original price was 84 ÷ 0.70 = $120. Adding 30% back to $84 would give $109.20, which is wrong.
How do I calculate what percent off something is?
Subtract the sale price from the original price, divide by the original price and multiply by 100. From $120 to $84 is $36 off, and 36 ÷ 120 = 0.30, or 30% off.
Why can't I add the discount percentage back to the sale price?
The discount was a percentage of the original price, which is larger than the sale price. Adding the same percentage of the smaller sale price recovers too little. You have to divide instead.
What does it mean if the sale price is higher than the original?
Then it isn't a discount; the price went up. The calculator will tell you to check the numbers. To measure an increase, use a percentage change calculator.