The formula
How it works
A discount is a percentage taken off the original price. The calculator shows both what you save and what you actually pay, so a “25% off” sticker turns into a real number before you get to the till.
FAQ
How do I work out a percent-off deal in my head?
For 25% off, take a quarter off the price; for 20%, take a fifth off. For odd numbers, find 10% (move the decimal one place) and scale up.
Can I stack two discounts?
Stacked discounts multiply, they do not add. 20% then another 10% off is 0.8 × 0.9 = 0.72, i.e. 28% off in total, not 30%.
How do I find the original price from a sale price?
Divide the sale price by (1 − discount/100). For example, $60 after a 25% discount means the original price was $60 ÷ 0.75 = $80.
Does the discount apply before or after sales tax?
Discounts are normally taken off the price first, and tax is then calculated on the reduced amount. Check the receipt if you are unsure, since a few jurisdictions tax the pre-discount price instead.
Is a discount the same as a markup?
No — a discount reduces a price by a percentage, while a markup increases a cost to set a selling price. Reversing a discount to get back to the original price is not the same calculation as adding a markup.
Why does a 50% discount feel bigger than two 25% discounts?
Because stacked percentages multiply rather than add, two successive 25% discounts only give 1 − 0.75 × 0.75 = 43.75% off, not 50%. A single 50% discount always saves more than splitting it into smaller stacked cuts.
Can I use this to check a coupon on top of a sale price?
Yes — first apply the sale discount to the original price, then run the result back through the calculator with the coupon percentage to get the final price after both reductions.
About the discount calculator
This calculator tells you the sale price after a percentage discount, and how much money you save. Shops advertise deals as “X% off”, which sounds simple but is easy to get wrong under pressure at the checkout. By turning the percentage into an exact amount, it helps you compare offers and check that the price you are charged is the price you were promised.
How to use it
Type the original (pre-sale) price and drag the slider to the advertised discount. The calculator instantly shows the amount you save and the final price you will pay. For example, an $80 jacket at 25% off saves you $20 and costs $60. Slide the discount up and down to see how much a bigger markdown is really worth, and change the currency to match the shop you are buying from.
The formula
The saving is the price times the rate, , and the final price is what is left, . Writing it this second way shows why a 100% discount makes the price zero and why 50% off leaves exactly half. If two discounts are applied one after another, multiply the factors rather than adding the percentages — a common trap that makes stacked deals look better than they are.
Where it is used
Shoppers use it during sales, clearance events and Black Friday to see the true price of a deal, while sellers use it to plan markdowns and promotions. The same percentage-off maths appears in coupons, student and staff discounts, and negotiated trade prices. Pairing it with a sales tax calculator gives the complete picture: first take the discount off, then add any tax to reach the amount you will actually pay.