Discount Calculator
Apply multiple discounts in their stated sequence and compare whole basket rows. Reverse mode recovers the original pre-discount price from a final pre-tax amount. The effective discount explains why two percentages cannot normally be added.
Your result
How the calculation works
Remaining-price factor = Π(1−discount/100). Final pre-tax price = original × factor. Reverse original = final / factor. Tax is then applied to the discounted basket.
Worked example
A $100 item discounted 20% then 10% costs $72 before tax, an effective 28% discount. At 5% tax, the total is $75.60. Reverse mode recovers $100 from a $72 final amount.
Assumptions and limitations
Up to twenty discounts and one hundred basket rows. A 100% discount cannot be reversed. No intermediate line/coupon rounding, eligibility rules, minimum purchase or capped promotions are assumed.
Enter quantity separately from unit price and verify whether your coupon applies before or after tax. Currency changes formatting only; it does not convert exchange rates.
Method reviewed 2026-10-13. Calculation standards · Report an issue