Sales math gets complicated fast once multiple discounts and tax stack up, this calculator handles percent off, stacked discounts, dollar amounts off, and reverse calculation from a known sale price.

How to use this calculator

1. Choose your mode: % Off, Final Price Known, or $ Amount Off.
2. Enter the Original Price and your discount(s), stacking multiple percentage discounts if needed.
3. Optionally add sales tax applied after the discount.
4. Read what You Pay and your total savings, with a full breakdown.

What this calculator does

This tool computes the final price after one or more percentage discounts, a flat dollar amount off, or works backward from a known sale price to find the discount percentage, plus applies sales tax after the discount if needed.

Why stacked discounts don’t simply add together

Two discounts of 20% and 10% stacked together do NOT equal a 30% discount, because the second discount applies to the already-reduced price, not the original price. A 20% discount followed by a 10% discount on a $100 item leaves $72, not the $70 that simply adding the percentages would suggest, this is why this calculator applies each stacked discount sequentially to the running price rather than summing the percentages first.

Why tax is applied after the discount, not before

Sales tax is calculated on the actual amount paid, which is the discounted price, not the original pre-discount price. Applying tax before the discount would overstate what the customer actually owes, this calculator’s ordering matches standard retail practice.

Frequently asked questions