How it works
Formula
Sale price = original × (1 − discount% ÷ 100). A second stacked discount multiplies again: final sale = original × (1 − d1 ÷ 100) × (1 − d2 ÷ 100). Amount saved = original − sale. Effective combined discount % = [1 − (1 − d1 ÷ 100) × (1 − d2 ÷ 100)] × 100 (so 20% then 10% is 28% off, not 30%). Optional sales tax is applied to the discounted sale price: tax = sale × tax% ÷ 100; you pay = sale + tax. Every money amount is rounded to the nearest cent.
Worked example
A $100 item at 20% off: sale = $80, you save $20. Add a second 10% off that discounted price: sale = $100 × 0.80 × 0.90 = $72 (effective 28% off). With 8% sales tax on a $50 item at 15% off: sale = $42.50, tax = $3.40, you pay $45.90.
Frequently asked questions
Is 20% off then 10% off the same as 30% off?
No. The second discount applies to the already-reduced price. 20% then 10% is a 28% combined discount: you pay 80% × 90% = 72% of the original. 30% off would leave you paying 70%.
Is sales tax charged on the original or the sale price?
In most U.S. states, sales tax is charged on the discounted (sale) price. Enter the tax rate for your location; this calculator applies it after the discount(s). Local rules can differ for coupons marked as "store" vs "manufacturer" — check your receipt or state DOR if it matters.
How do I enter a fixed dollar-off coupon?
Convert it to a percent of the original price first (dollar-off ÷ original × 100), or subtract it yourself and enter the reduced amount as the original price with 0% discount. This tool is built for percent-off discounts.