Discount Calculator

To calculate a percentage discount, multiply the original price by the discount percentage and divide by 100; that gives you the discount amount in dollars. Subtract that amount from the original price to get the sale price. Example: 20% off $80 means discount = 80 × 20 ÷ 100 = $16, so the final price is $64. Tax, if applicable, is then calculated on the discounted price, not the original.

Percentage discounts scale with the original price (e.g., 20% off $100 = $20 savings; 20% off $50 = $10 savings), so the dollar amount you save grows with the price. Fixed amount discounts give the same dollar reduction regardless of price (e.g., $20 off applies the same to a $100 or a $50 item). For expensive items, a percentage discount often saves more; for lower-priced items, a fixed discount can be easier to compare. Use the calculator to see which saves you more for your specific purchase.

Tax is calculated on the discounted price, not the original. First apply the discount to get the sale price, then multiply the sale price by your tax rate to get the tax amount; add tax to the sale price for the total you pay. Calculating tax on the reduced amount lowers your total bill compared to taxing the original price. In most jurisdictions, this is how sales tax is applied at the register.

It depends on the retailer. Some allow stacking (e.g., a store-wide 20% off plus a $10 coupon), so you apply one discount to the original price, then apply the next to the reduced price. Others allow only one discount (the best one). Stacked discounts are applied in sequence, not added as percentages—20% off then 10% off is not 30% off. Always read the store's terms and conditions or ask at checkout to avoid surprises.

The effective discount percentage expresses a fixed dollar discount as a percentage of the original price. Formula: (Fixed Discount Amount ÷ Original Price) × 100. For example, $15 off a $60 item is 25% effective. This lets you compare "20% off" versus "$15 off" on the same item—whichever gives the lower final price is the better deal. This page does not print a separate effective-percent figure. Compare the two modes by the amount off and the final price.

This calculator handles one item per run. For several items, run it once per item and add the discount amounts (or final prices) for a total. If every item has the same percentage off, you can instead add the original prices, then apply the discount once to that total—the result is the same. For mixed discounts (e.g., different percentages per item), calculate each item separately and sum the results.

A percent discount is original price × (percent ÷ 100). A fixed discount is the dollar amount you enter. Amount off is that discount only. Sales tax is the discounted price × (tax rate ÷ 100). Final price is the discounted price plus that tax. A percent above 100, or a fixed discount larger than the price, is rejected. Source: NIST SP 811 measurement guidance: https://www.nist.gov/pml/special-publication-811.