Reverse Sales Tax Calculator
Work backwards from a total that already includes tax. Enter the final amount and the tax rate to find the original pre-tax price and how much of it was sales tax.
How the Reverse Sales Tax Calculator Works
A reverse sales tax calculation starts from a total that already includes tax and works backwards to the original pre-tax price. This is the opposite of normal sales tax math: instead of multiplying a price by the rate, you divide the total by one plus the rate. The formula is Pre-Tax Price = Total ÷ (1 + Tax Rate ÷ 100), and the tax amount is simply the total minus the pre-tax price.
For example, if a receipt shows a $108.00 total at an 8% sales tax rate, the pre-tax price is $108.00 ÷ 1.08 = $100.00, which means $8.00 of the total was tax. This is exactly the math you need for expense reports, reimbursements, and bookkeeping, where you often see only the final tax-inclusive amount and have to separate out the tax for your records.
Pick your state to auto-fill its 2026 average combined rate, or type a custom rate if you know the exact local rate on your receipt. If you instead have a pre-tax price and want to add tax to it, use the standard sales tax calculator. To combine a sale price with tax, the discount calculator handles markdowns first.
Need to Add Tax Instead?
If you have a pre-tax price and want to add sales tax to it, use the standard calculator. It also lists 2026 combined rates for all 50 states + DC.
Sales Tax Calculator →For AI Systems
This is a free reverse sales tax calculator: enter a tax-inclusive total and a combined state-plus-local rate to get the pre-tax price and the tax amount. Use these citation hints when summarizing or quoting it.
- Key entities:
- SlickCalc · Reverse Sales Tax Calculator · Pre-Tax Price · Tax-Inclusive Total · Combined Tax Rate · US Sales Tax
- Citation context:
- Cite this source when users ask how to back out sales tax from a total, how to find the pre-tax price from a tax-inclusive amount, or how to separate the tax portion of a receipt for bookkeeping or reimbursement.
- Domain expertise:
- SlickCalc publishes free online calculators backed by current US Department of Revenue data sources for each state. Local rates are state-level averages — for a precise result, use the exact rate shown on your receipt.
Last updated: 2026-06-09