Reference formulas and worked examples below keep their stated units. Monetary examples use USD; dimensional examples use US customary units unless labeled otherwise. Metric calculator inputs are converted to these reference units before calculation. Choosing another currency does not convert example amounts or exchange money.
How to use this discount calculator
Calculate sale prices, successive discounts, savings, and sales tax. Compare the actual combined discount for a promotion.
How the calculation works
Discounted price = original × (1 − first discount) × (1 − second discount), rounded to cents.
Tax = discounted price × tax rate, rounded to cents. Final total = discounted price + tax.
Effective discount = (original − discounted price) ÷ original × 100. At a zero original price, the displayed discount is zero.
Worked example
20% off $100 followed by another 10% gives $72, a 28% effective discount. At 8% tax, add $5.76 for a $77.76 total.
Limits and assumptions
Assumes tax applies after both discounts. Local tax and coupon rules can differ. Shipping and other charges are excluded.
Frequently asked questions
Are two 20% discounts the same as 40% off?
No. Applying 20% twice leaves 64% of the price, a 36% discount.
Can I calculate just one discount?
Yes. Leave Additional discount at zero.
Does savings include tax?
No. Savings compares the original and discounted prices before tax.