Discount calculator
Enter the price and the percent off to see 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.
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.
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.
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.
Sources and legal basis
As of:
Related tools
- Tip calculator and bill splitterWork out the tip, split the bill between any number of people and round up each share or the total to $1, $5 or $10 – and see the tip rate you really pay.
- VAT calculator for France and SpainAdd or remove French VAT (TVA 20%, 10%, 5.5%, 2.1%) or Spanish VAT (IVA 21%, 10%, 4%) – net to gross and back, rounded to the cent, with official sources.
- Percentage CalculatorFree percentage calculator: find X% of a number, what percent one number is of another, percentage change, increase and discount – with formula and steps.
- Inflation calculator – value of a dollar over timeInflation calculator using official annual CPI data from the BLS since 1913: what a dollar amount is worth in another year, plus total and average inflation.
- Electricity cost calculator for appliancesWork out what an appliance costs to run: enter watts, hours per day, days per week and your rate per kWh to get kWh and cost per day, month and year.
- EV charging cost calculatorWork out what charging your electric car costs at home and at a public charger – from battery size, state of charge, charging losses and your price per kWh.