Discount Calculator

A discount is a reduction from an item's original price, usually shown as a percentage off. Knowing the final price and the exact amount saved helps you judge whether a sale is genuinely good value.

This calculator instantly converts an original price and a discount percentage into the sale price and the money you save.

"An extra 20% off sale prices" reads as though it should be added to the discount already applied, and it never is. The second reduction is taken from the already-reduced price, not from the original, so the discounts multiply rather than sum.

Taking 50% off and then a further 20% off gives 60% off in total, not 70%. On a $200 item that is a final price of $80 rather than the $60 a true 70% discount would produce, a $20 difference on a single item. Three stacked reductions of 30%, 20% and 10% come to 49.6% off, not 60%.

• The order the discounts are applied in does not change the result, since multiplication is commutative.
• A coupon applied before tax reduces the tax as well; applied after, it does not. Check which the till is doing.
• The same arithmetic works in reverse: a 20% price rise followed by a 20% cut leaves you below where you started, not back at it.

Two closely related calculations get confused constantly. "25% off $80" is a reduction, giving $60. "25% of $80" is a portion, giving $20. The words differ by one preposition and the answers differ by the whole remainder.

The same trap appears when working backwards from a sale price. If an item is $60 after 25% off, the original was $60 ÷ 0.75 = $80, not $60 + 25%, which would give $75. Adding the percentage back applies it to the wrong base.

• To reverse a discount, divide by (1 − discount), do not multiply by (1 + discount).
• A price advertised as "half price" and one advertised as "50% off" are the same thing; "buy one get one half price" is a 25% discount across the two items.
• Unit pricing is the reliable comparison when discounts are attached to different pack sizes.