Util Tools How to calculate a discount
A discount is a percentage off the original price. The sale price is original * (1 - discount/100), and the amount you save is the original minus the sale price. For a $80 item at 25% off, you save $20 and pay $60. This calculator works out the sale price, the savings, the percentage off, and even the original price when you only know the discounted one.
Finding the original price from a sale price
Sometimes you know the final price and the discount and want the original. Reverse the formula: original = sale price / (1 - discount/100). An item on sale for $60 after 25% off was originally $60 / 0.75 = $80. This is handy for checking whether an advertised "was" price is genuine.
Why stacked discounts do not simply add up
A common misconception is that "20% off then an extra 10% off" equals 30% off. It does not. The second discount applies to the already-reduced price, so the discounts stack sequentially: 20% off $100 is $80, then 10% off $80 is $72, an effective 28% off, not 30%. The calculator handles stacked promotions correctly so you see the true final price.
Discounts vs. rebates
A discount reduces the price at the time of purchase, so you pay less immediately. A rebate is money returned after the sale, usually requiring a claim, so you pay full price first and recover part of it later. Both lower your net cost, but a discount is simpler and guaranteed, while a rebate depends on you actually submitting the claim.
Last updated: July 2026