Percent-off discount calculator
Work out how much a discount saves, what the item costs after the reduction, and the total after tax.
Tax, where you add it, is applied to the discounted price.
How this calculator works
A percentage discount reduces the price by that share of the original: 25% off $200 saves $50 and leaves $150. Sales tax, where it applies, is charged on the discounted price rather than the original price, which is why the order of operations matters.
Retail discounts are often stacked, and the arithmetic surprises people. Two successive 20% discounts do not equal 40% off — they equal 36% off, because the second 20% applies to a price that has already been reduced. To handle stacked discounts, apply them one after another, or enter the equivalent single discount: 1 − (1 − d1)(1 − d2). Similarly, a “25% off, then an extra 10%” is 32.5% total, not 35%.
The formula
Discount = original price × discount% ÷ 100. Final price = original − discount. With optional tax on the discounted price:
saved = price · d / 100
final = price · (1 − d / 100)
total = final · (1 + tax / 100)
stacked = 1 − (1 − d1)(1 − d2)For a sale price and the discount, the implied original price is final ÷ (1 − d/100).
Worked example
A 200 item at 25% off costs $150.00 after the discount — a saving of $50.00. With 0% sales tax added on the reduced price the total is $150.00, including 0 of tax.
Common mistakes
- Adding stacked discounts. 20% plus 20% is 36% off, not 40%. Apply each discount to the already-reduced price.
- Adding the tax to the original price. Sales tax applies to what you actually pay after the discount.
- Assuming the ticket price is the reference price. Some retailers raise the original price before advertising a discount. Compare the final price with the market, not the crossed-out number.
Frequently asked questions
How do I calculate 25% off?
Multiply the price by 0.25 to get the saving, then subtract it: $200 × 0.25 = $50 saved, so the final price is $150. Alternatively multiply by 0.75.
What does an extra 20% off mean?
The 20% applies to the already-discounted price, not the original price. Two 20% discounts compound to 36% off the original.
Is it cheaper to buy with a discount or with a coupon after tax?
Compare the final out-of-pocket total. A percentage discount reduces the price and therefore the tax charged; a fixed-amount coupon reduces the price but may still be taxed differently depending on local rules.
Related calculators
Sales Tax CalculatorTip & Bill Split CalculatorVAT CalculatorGST Calculator · All Salary & Tax calculators