Discount Calculator (with optional sales tax)
Enter the original price and the discount percentage to see the final price and how much you saved. Add a sales tax rate if your jurisdiction adds tax after the discount.
How it works
How discount math works
Discounted price = original × (1 − discount/100). A 20% discount on a $100 item leaves $80. Sales tax is applied to the discounted amount, not the original — so $80 × (1 + 8% tax/100) = $86.40 final.
The 'you save' amount is the discount in dollars: original × discount/100. For our $100 example at 20% off, you save $20. This is what shoppers naturally want to see — not just the percent.
Stacking discounts
Two discounts don't add. A '20% off' coupon on top of a '20% off sale' is 36% off total, not 40% — because the second discount applies to the already-reduced price (0.8 × 0.8 = 0.64 = 36% off the original).
To stack, run the calculator twice: first with the bigger discount, then plug the result back in as the new 'original' with the second discount. Or, if you have multiple coupons, multiply (1 − d1/100) × (1 − d2/100) × ... and subtract from 1 to get the total effective discount.
Tax timing varies by country
United States: sales tax is added at the register, after any discounts. Use this calculator's tax field directly. Each state and city has its own rate (NYC 8.875%, LA 9.5%, no tax in Oregon).
EU/UK: VAT is typically already in the displayed price, so don't double-count. Set tax to 0 if the price you entered is VAT-inclusive. Japan's consumption tax is also usually included in displayed prices (総額表示).
Sometimes shipping is taxable, sometimes not. This calculator assumes the price you enter is the taxable amount. For complete cart math, total your taxable items separately.
Frequently asked questions
›Is the discount applied before or after tax?
Almost always before. The discount reduces the taxable amount; tax is then added to the discounted price.
›How do I stack multiple coupons?
Apply them sequentially: original × (1 − d1/100) × (1 − d2/100). Use the calculator twice or compute manually.
›What's the formula for 'percent off'?
Final = original × (1 − discount/100). Savings = original × discount/100.
›Does this work for buy-one-get-one (BOGO)?
Roughly — BOGO half off is effectively a 25% discount on a two-item bundle. For exact BOGO math, divide your bundle price into per-item amounts first.
›Why did I see a 'comparison' price that wasn't real?
Some retailers inflate the 'original' price to make discounts look bigger. Compare to other stores or historical prices to know the real discount.
›Are stacking 'mystery' discount codes worth it?
Run the math both ways. Often a single big code beats two small ones because of the multiplicative effect.
›How do I find the discount % from two prices?
Discount % = (original − sale) / original × 100. Or use our percentage calculator's 'percent change' mode.
›Is the data sent anywhere?
No. Calculation runs in your browser.
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