— Everyday Math
Discount Calculator
Enter a price and a discount to see what you pay and what you save — take a percentage or a flat amount off, stack two or three offers, add sales tax, or work backwards from a sale price to the percentage off.
Sale price
$2,249.25
- You save
- $749.75
- Discount
- 25%
— How it works
Sale price = original × (1 − discount%/100), or original − flat amount. Stacked discounts multiply: 20% then 10% leaves 0.8 × 0.9 = 72% of the price — a 28% reduction. Sales tax applies to the discounted price.
Sale price and what you save
A discount comes off the original price, and the two figures that matter are what you pay and what you save. A percentage discount multiplies the price by one minus the rate, so a 25% discount leaves 75% of the price; a flat discount simply subtracts a fixed amount. Toggle the discount field between % and a flat amount and the calculator shows the sale price, the amount saved, and the discount expressed the other way — so a flat amount also tells you the percentage it represents, and a percentage tells you the cash off.
Worked example — a $2,999 item at 25% off: You save $2,999 × 25% = $749.75, so the sale price is $2,249.25. Add a stacked 10% (under Advanced options) and the two multiply to 32.5% off — not 35% — bringing the price to $2,024.33.
Stacked discounts multiply, they don’t add
When two discounts apply one after another you cannot add them. 20% off and then a further 10% off is not 30% — the second cut comes off the already-reduced price, so you keep 0.8 × 0.9 = 0.72 of the original, a 28% total reduction. The calculator’s “effective combined discount” works this out for any two or three stacked offers, which is the honest number to compare against a single headline discount.
This is exactly why a “20% off, plus an extra 10% at checkout” deal is worth less than a flat 30% off — and the gap widens the more discounts you stack.
Sales tax, and working backwards
Sales tax, VAT or GST is charged on the discounted price, not the original — so a discount lowers the tax you pay as well as the price. Enter a tax rate under Advanced options and the calculator adds it to the sale price for the final amount you actually hand over. To go the other way, switch the mode to “the % off”: enter the original price and the sale price you are being offered, and it returns the percentage discount that represents — handy for checking whether a “half price” claim is really 50% off.
— Reader questions
How do I calculate a percentage discount?
Multiply the price by the discount as a decimal to get the amount off, then subtract it. A 25% discount on $2,999 is 2,999 × 0.25 = $749.75 off, for a sale price of $2,249.25. This calculator does it instantly and also shows the saving as both an amount and a percentage.
Are two stacked discounts the same as adding them?
No. A 20% discount followed by a 10% discount is 28% off, not 30%, because the second applies to the already-reduced price (0.8 × 0.9 = 0.72, so you pay 72%). Enter both under Advanced options and the “effective combined discount” shows the true total.
Is sales tax applied before or after the discount?
After. The discount reduces the price first, then tax is charged on the discounted amount — so a discount also lowers the tax. Enter your tax rate under Advanced options to see the final price including tax.
How do I find what percentage off a sale price is?
Switch the mode to “the % off”, enter the original price and the sale price, and the calculator returns the discount as a percentage. For example, $2,999 marked down to $2,249 is about 25% off.
What is the difference between a flat and a percentage discount?
A flat discount takes a fixed amount off regardless of price; a percentage discount takes a share of the price, so it is larger on more expensive items. Toggle the discount field between % and a flat amount — either way the calculator shows the equivalent percentage.