Discount Calculator

Sale tags are built to make you feel like you are getting a deal, not to make the math easy. “25% off” on an $80 jacket is simple enough. “Extra 15% off clearance” on a $49.99 shirt, with tax on top, is not. This calculator does the arithmetic so you can judge the deal itself: is it actually a good price, or just a big percentage on an inflated one?

Original price and percent off, and it answers straight away.

The trap: stacked discounts

Two discounts do not add. A 20% discount followed by an extra 10% off is not 30% off. The second discount applies to the already reduced price: $100 becomes $80 after 20% off, then $72 after the extra 10%. That is 28% off in total, not 30%. Stores are not necessarily being sneaky, this is just how sequential percentages work, but it is worth knowing before you compare “30% off” at one shop with “20% plus an extra 10%” at another.

The two lines of math

Sale price = Original price × (1 − discount ÷ 100)

Amount saved = Original price × discount ÷ 100

For $80 at 25% off: sale price = $80 × (1 − 0.25) = $80 × 0.75 = $60. Amount saved = $80 × 0.25 = $20. The two numbers always add back up to the original price, which is a handy way to check your answer.

Step by step: turn the discount into a decimal, 25 ÷ 100 = 0.25. Amount saved: $80 × 0.25 = $20.00. Sale price: $80 − $20.00 = $60.00. Check: $60.00 + $20.00 = $80.00. All figures rounded to the nearest cent.

Enter the original price, the price before any discount, and the percent off. The calculator answers with the sale price, what you pay, and the amount saved. If the store offers a second discount, it applies to the sale price, not the original.

The sale price is what leaves your wallet before tax. The amount saved is the discount in dollars, often more useful than the percentage: 50% off a $10 item saves you $5, while 10% off a $400 item saves you $40. Percentages hide the size of the deal. Dollars do not.

Three price tags

$120 at 30% off: you pay $84.00, you save $36.00.

$49.99 at 15% off: you pay $42.49, you save $7.50.

$100 at 20% off, then an extra 10% off: you pay $72.00, you save $28.00, not $30.00.

It works backwards too. If a $120 jacket sells for $84, you saved $36, and $36 ÷ $120 × 100 = 30% off. Any two of the three numbers gives you the third.

Before you pay

How do I calculate a discount?

Multiply the price by the discount percentage divided by 100 to get the amount saved, then subtract it from the price. For $80 at 25% off: $80 × 0.25 = $20 saved, $80 − $20 = $60 to pay. The calculator above does the same math instantly.

Is the sale price before or after tax?

Before tax. Sales tax is charged on the price you actually pay, which is the sale price in most U.S. states. To get the full checkout total, run the sale price through our Sales Tax Calculator.

How do I spot a fake discount?

Compare the sale price with what the item usually sells for elsewhere, not with the “was” price on the tag. A “was $200, now $100” deal is only a deal if the item genuinely sold for $200. Check the price at two other shops before deciding.

Not the one you wanted?

The Percentage Calculator handles any percentage problem, including increase and decrease. The Sales Tax Calculator adds the tax on top of the sale price. The Tip Calculator does percentages at the restaurant table. The Savings Goal Calculator puts the money you did not spend to work. How to Calculate a Percentage explains the math behind all of this. Or browse All Finance Calculators and All Calculators.

General information and planning only. Not financial, investment, tax, or legal advice. Store pricing, tax rules, and return policies vary, so check with a qualified professional before making financial decisions.

No external source needed, the math is standard arithmetic.

By Lucas Meyer · Last updated 15 October 2026