Math

Discount calculator.

The final price after a percent off — and the dollars you save.

Working out a sale price

A percent-off discount is simple: multiply the price by the discount to get the saving, then subtract. 25% off $120 is 0.25 × 120 = $30 saved, for a $90 sale price. A useful shortcut for the final price is to multiply by one minus the discount — $120 × 0.75 = $90 — which skips the subtraction step. Watch out for "stacked" discounts: an extra 10% off an already-30%-off price isn't 40% off, because the second discount applies to the reduced price (it works out to 37% off). Sales tax, if any, is added to the discounted price — the sales tax calculator handles that.

Working backwards to the original price

Sometimes you know the sale price and the discount but not the original. Divide the sale price by one minus the discount: a $90 item marked 25% off started at 90 ÷ 0.75 = $120. The same trick turns a dollar saving into a percent — divide the amount saved by the original price. If a $200 jacket is now $150, you saved $50, and 50 ÷ 200 = 0.25, so it's 25% off.

This matters because retailers often advertise the dollars off rather than the percent, and the two feel different at a glance. A "$40 off" tag is a big deal on a $60 item (67% off) but minor on a $600 one (about 7%). Converting to a percent lets you compare deals across price points on equal footing.

FAQ

How do I calculate a sale price?
Multiply the original price by the discount percent to get the amount saved, then subtract it. Or multiply by (1 − discount): $120 at 25% off is $120 × 0.75 = $90.
Do two stacked discounts add together?
No. A 30% discount followed by an extra 10% off applies the second to the already-reduced price, so it's 0.70 × 0.90 = 0.63, or 37% off total — not 40%.
How do I find the original price from a sale price?
Divide the sale price by one minus the discount. A $90 item at 25% off started at 90 ÷ 0.75 = $120. This reverses the usual calculation, which multiplies the original by (1 − discount).
How do I turn a dollar amount off into a percent discount?
Divide the amount saved by the original price. A $50 discount on a $200 jacket is 50 ÷ 200 = 0.25, or 25% off. Converting to a percent lets you compare deals fairly across different price points.

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