Discount calculator
Enter the price and the percent off and this discount calculator shows the sale price and how much you save. Stacked discounts are applied one after another, the way stores do it. You can also work out the percent off between two prices or the original price before a sale.
Example: What do you want to calculate: Sale price after discount · Original price 100 · Discount 20 % off → Sale price: 80.00. Source: 16 CFR § 233.1, FTC Guides Against Deceptive Pricing – former price comparisons (via Cornell LII). Updated: .
How it is calculated
Discount formula
Sale price = price × (1 − discount ÷ 100) and savings = price × discount ÷ 100. Example: a jacket at 49.90 with 30% off costs 49.90 × 0.70 = 34.93, so you save 14.97. Mental shortcut: 10% of 49.90 is 4.99, so 30% off is about 15.
How to calculate a discount
- Under “What do you want to calculate?”, choose the sale price after discount, the percent off from two prices, or the original price.
- Enter the price and the percent off; add stacked discounts in the optional fields.
- Read the sale price and how much you save.
Example: 20% off 80 is 80 × 0.8 = 64, a saving of 16. With an extra 10% off, you pay 64 × 0.9 = 57.60 – 28% off in total, not 30%.
Stacked discounts: 20% + 10% is not 30% off
An extra discount (“take an additional 10% off”) is almost always applied to the already reduced price. That is why the percentages multiply instead of adding up:
Total discount = 1 − (1 − d₁) × (1 − d₂) × …
| Step | Calculation | Price |
|---|---|---|
| Original price | 100.00 | |
| 20% off | 100 × 0.80 | 80.00 |
| extra 10% off | 80 × 0.90 | 72.00 |
Together that is 28% off (1 − 0.8 × 0.9), not 30%. The order does not matter: 10% first and then 20% also ends at 72. Another example: 80 with 25% off plus an extra 10% off comes to 54, a total discount of 32.5%.
How to calculate the percent off between two prices
Percent off = (original price − sale price) ÷ original price × 100. Always divide by the original price. Example: marked down from 80 to 60 = 20 ÷ 80 = 25% off. A TV reduced from 129.99 to 99.99 is 30 ÷ 129.99 = 23.08% off.
How to find the original price
If you only know the sale price and the discount: original price = sale price ÷ (1 − discount ÷ 100). 60 after 25% off was 60 ÷ 0.75 = 80 before – not 75, because the 25% was taken from the higher original price. 39.99 after 20% off was 49.99.
Sales tax and “was” prices
If sales tax is added at checkout, it is charged on the discounted price: apply the discount first and the tax afterwards. The US Federal Trade Commission’s pricing guides say a “former price” used in a price comparison should be a genuine price at which the item was openly offered for a reasonably substantial period – an inflated “was” price makes the bargain a false one (16 CFR § 233.1).
Each discount step is rounded to the cent, as on a receipt.
More calculators: general percentage questions go to the percentage calculator, bulk pricing to the volume discount calculator, package sizes to the unit price calculator, and restaurant bills to the tip calculator.
Frequently asked questions
How do I calculate 20% off?
Multiply the price by 0.8 (that is 1 − 0.20). 100 becomes 80 and you save 20. In general: sale price = price × (1 − discount ÷ 100).
Is 20% off plus an extra 10% off the same as 30% off?
No. The extra 10% comes off the already reduced price: 100 → 80 → 72. That is 28% off in total, calculated as 1 − 0.8 × 0.9.
How do I work out the percentage discount from two prices?
Subtract the sale price from the original price, divide by the original price and multiply by 100: (80 − 60) ÷ 80 × 100 = 25%. If the new price is higher, it is a markup, and the calculator shows that instead.
How do I find the original price from the sale price?
Divide the sale price by (1 − discount ÷ 100). 60 after 25% off: 60 ÷ 0.75 = 80. Adding 25% back on (60 × 1.25 = 75) gives a price that is too low.
How do I calculate a discount in Excel or Google Sheets?
With the price in A2 and the discount formatted as a percentage in B2, use =A2*(1-B2). For two stacked discounts: =A2*(1-B2)*(1-C2). Percent off from an original price (A2) and a sale price (B2): =(A2-B2)/A2.
Is the discount taken before or after sales tax?
With a percentage discount and a fixed tax rate the order makes no difference to the total. If tax is added at checkout, enter the pre-tax price here and add your local sales tax to the result.
What is 30% off 50?
30% of 50 is 15, so the sale price is 35. Quick check: 50 × 0.7 = 35.
How do I calculate 15% off in my head?
Find 10% by moving the decimal point: 10% of 80 is 8. Half of that is 5% = 4. Together 15% = 12, so the sale price is 68.
How do I combine a coupon with a percent discount?
Enter the coupon value in “Coupon / fixed amount off”. It is subtracted last, from the price after the percentage discounts: 100 with 20% off and a 10 coupon comes to 70. Whether a coupon applies before or after the percentage is set by the store’s terms, and that changes the final price.
Sources and legal basis
As of: · Editorial policy
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