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Work out a sale price, check how much a percentage or dollar discount actually saves you, find the discount percentage between two prices, or work backwards from a sale price to the original price. You can also stack several discounts together and see the true combined saving, not just the numbers added up.
Add as many discounts as apply, in the order they are taken.
Tax rules vary by place and transaction type. This is an estimate, not tax advice.
How to use the Discount Calculator
Choose the tab that matches what you already know:
- % off – you know the price and a percentage discount, and want the sale price.
- Amount off – you have a dollar or pound amount off instead of a percentage.
- Find the % – you know the price before and after the discount, and want the percentage.
- Original price – you only know the sale price and the discount percentage, and want the price before the discount.
- Stack discounts – two or more discounts apply one after another, such as a sale plus a coupon.
Turn on "Add tax" if you also need the total after tax is added to the discounted price.
How discount calculations work
A discount reduces a price by a percentage or a fixed amount. The important habit is knowing which number is the "before" price and which is the "after" price, since mixing them up is the most common mistake. A percentage discount is always worked out on the original, pre-discount price, not on the sale price.
Discount formula
- Discount amount = original price × discount % ÷ 100
- Final price = original price − discount amount
- Discount % from two prices = (original price − sale price) ÷ original price × 100
- Original price from a sale price = sale price ÷ (1 − discount % ÷ 100)
- Stacked discounts = original price × (1 − D1/100) × (1 − D2/100) × …
How to calculate a discount
Example: a jacket costs $120 and is 25% off.
- Discount amount = 120 × 0.25 = $30
- Final price = 120 − 30 = $90
Fixed amount example: a $250 order has a $50 coupon. Final price = 250 − 50 = $200. As a percentage, that coupon is 50 ÷ 250 × 100 = 20% off.
Finding the percentage: a jacket was $200 and is now $150. Discount amount = 200 − 150 = $50. Discount % = 50 ÷ 200 × 100 = 25%.
Reverse discount calculation
Sometimes you know the sale price and the discount, and want the original price, for example to check if a "50% off" sticker is genuine. Divide the sale price by (1 − discount ÷ 100) rather than simply adding the percentage back on.
Example: a pair of shoes is on sale for $80 at 20% off. Original price = 80 ÷ (1 − 0.20) = 80 ÷ 0.80 = $100. Note that this is not the same as adding 20% to $80, which would only give $96.
How stacked discounts work
When two discounts apply to the same purchase, such as a storewide sale plus a coupon code, they are normally applied one after the other, not added together. Each discount is calculated on the price that is left after the previous discount, so the total saving is always a little less than simply adding the percentages.
Example: a $100 item gets 20% off, then a further 10% off. After the first discount: 100 × 0.80 = $80. After the second: 80 × 0.90 = $72. The combined discount is (1 − 72/100) × 100 = 28%, not 30%. The gap grows with bigger or more numerous discounts, so always calculate stacked discounts in sequence rather than adding the percentages.
Discount vs markup vs profit margin
A discount is a reduction from a selling price, worked out from the seller's or shopper's point of view. Markup and profit margin describe the gap between what a seller pays for something and what they sell it for, not a reduction from a listed price. If you are the one setting the discount, check that it still leaves you a profit: use the profit margin calculator or the markup calculator to see your margin after the discounted price, and the break-even calculator to check the discount still covers your costs.
Real-world uses of a discount calculator
- Working out the real sale price before you buy, especially with stacked coupons or loyalty discounts.
- Checking that a shop's "was/now" pricing is calculated correctly.
- Sellers pricing a sale or clearance, then checking the discounted price still leaves a profit.
- Working out the price including tax on a discounted item; many places charge tax on the price after the discount, using the same rate as the UK VAT calculator.
- Sellers who take payments through PayPal can check what a discounted sale actually leaves after fees with the PayPal fee calculator.
Common discount calculation mistakes
- Adding stacked discounts together. 20% then 10% is a 28% saving, not 30%.
- Working out the percentage on the wrong price. A discount percentage is normally based on the original price, not the sale price.
- Reversing a discount by adding the percentage back. $80 after 20% off does not become $100 by adding 20% of $80; you need to divide by 0.80, as shown above.
- Applying tax before the discount when it should be applied after, or the other way round. Check which order your local rules or the shop uses.
Frequently asked questions
How do I calculate a 20% discount?
Multiply the original price by 0.20 to get the discount amount, then subtract it from the original price. On $100, a 20% discount is $20 off, for a final price of $80.
How do stacked discounts work?
Apply each discount to the price left after the one before it, not to the original price each time. Two discounts of 20% and 10% give a combined saving of 28%, not 30%.
How do I find the original price before a discount?
Divide the sale price by (1 minus the discount as a decimal). For a $80 sale price after 20% off, the original price is 80 ÷ 0.80 = $100.
Is a discount the same as a markup or margin?
No. A discount reduces a selling price. Markup and margin describe the difference between a cost and a selling price. See the markup and profit margin calculators if you need those instead.
Should tax be calculated before or after the discount?
This depends on local rules and how the seller structures the sale, and it can go either way. This calculator applies tax after the discount, which is common, but check the receipt or the rules that apply to you if it matters.
Can a discount be more than 100%?
No. A 100% discount already means the item is free. A discount above 100% is not meaningful, and this calculator will not accept one.