How to use the Discount Calculator
- Choose Sale price to apply a discount, or Original price to work backwards from a sale price.
- Enter the price and the discount, as a percentage or an amount off.
- Tick Add an extra discount for offers like “extra 10% off sale items”, and add sales tax to see the checkout total.
- Read the final price, the amount you save and the total discount percentage.
Features
- Percent off or a fixed amount off
- Stacked second discount applied the right way
- Optional sales tax added after the discount
- Reverse mode finds the original price from a sale price
- Effective total discount percentage
How to calculate a discount
A percentage discount is a share of the original price. Multiply the price by the discount rate to find the saving, then subtract it: Sale price = Price × (1 − Discount ÷ 100). For 25% off 80, the saving is 80 × 0.25 = 20 and the sale price is 60. With an amount-off coupon you simply subtract the amount.
A mental shortcut: 10% of a price is the price with the decimal point moved one place to the left. Double it for 20%, halve it for 5%, and take a quarter of the price for 25%.
Stacked discounts do not add up
When a store offers “20% off, plus an extra 10% at checkout”, the second discount applies to the already reduced price. The combined discount is 1 − (1 − 0.20) × (1 − 0.10) = 28%, not 30%.
| Discounts | Combined discount | Price of a 100 item |
|---|---|---|
| 20% + 10% | 28% | 72.00 |
| 30% + 20% | 44% | 56.00 |
| 50% + 20% | 60% | 40.00 |
| 40% + 40% | 64% | 36.00 |
The order of two percentage discounts does not matter: 10% then 20% gives the same 28% as 20% then 10%. A fixed amount off is different. Taking 10 off a 100 item before a 20% discount leaves 72, while taking it off after leaves 70. This calculator applies an amount-off discount first and the extra percentage second, so read the terms of your offer.
Finding the original price
If you know the sale price and the percentage, divide instead of multiplying: Original price = Sale price ÷ (1 − Discount ÷ 100). A jacket on sale for 60 at 25% off was originally 60 ÷ 0.75 = 80. A common mistake is adding 25% back to 60, which gives 75 and understates the original price.
Adding sales tax
In most places sales tax is charged on the price you actually pay, after discounts. A 60 sale price with 8% tax costs 64.80 at checkout. In some US states, manufacturer coupons are treated differently and tax is charged on the price before the coupon, so a receipt can differ slightly. For more on tax, see the Sales Tax Calculator.
Shopping tips
- Compare final prices, not percentages. 30% off an inflated “was” price can cost more than 10% off elsewhere.
- Check the unit price when a discount comes with a bigger pack.
- “Buy one, get one 50% off” on two items of the same price is a 25% discount on the pair.
For other percentage questions, try the Percentage Calculator. Figures are estimates for information only and are not financial advice; the price charged at checkout is what counts.
Frequently asked questions
How do I calculate 30% off?
Multiply the price by 0.70. For example, 30% off 150 is 150 × 0.70 = 105, a saving of 45.
How do two discounts combine?
Multiply what remains after each: 20% and then 10% leaves 0.80 × 0.90 = 0.72 of the price, a 28% total discount rather than 30%.
How do I find the original price from the sale price?
Divide the sale price by one minus the discount rate. A sale price of 60 at 25% off means 60 ÷ 0.75 = 80.
Is sales tax applied before or after the discount?
Usually after: you pay tax on the discounted price. The calculator adds tax after all discounts.
Is percent off or amount off better?
Percent off scales with the price, while amount off is a fixed saving. On cheaper items an amount-off coupon is often worth more; on expensive items a percentage usually wins.