How to Calculate a Discount and Sale Price (Free Guide)
By the 325Tools Team · Updated 2026-05-30
Spotting a "30% off" sticker is easy; knowing the exact price you will pay is the useful part. Here is the simple way, plus a free Discount Calculator.
The discount formula
Sale price = original price × (1 − discount% ÷ 100)
Example: a $80 item at 25% off → 80 × (1 − 0.25) = 80 × 0.75 = $60. You save $20.
How much did I save?
Savings = original price × (discount% ÷ 100) — in the example, 80 × 0.25 = $20.
Stacking two discounts
Discounts stack multiplicatively, not by adding. 20% then 10% off is not 30% off: 100 → 80 → 72, an effective 28% off. Apply one in the Discount Calculator, then reuse the result for the next.
Don't forget tax
If tax applies after the discount, run the sale price through the VAT Calculator.
Frequently asked questions
Is the discount applied before or after tax? Usually before tax — discount first, then tax on the reduced price.
Is my data uploaded? No. The calculation happens in your browser.
When a simple discount calculation isn't enough
A percent-off formula answers "what will I pay," but it doesn't tell you whether a deal is good. Watch for cases it can't capture: a "buy one get one 50% off" promo is really 25% off two items, not 50%; a "$10 off $50" coupon is a 20% discount only if you spend exactly $50, and less the more you add; and clearance prices marked off an inflated "original" price can hide a small real saving. For the seller's side — checking the margin that survives a discount — use the Profit Margin Calculator instead, since cutting price below cost is easy to do by accident.