Reverse Sales Tax Calculator
Last updated: July 2026
Find the pre-tax price and tax amount from a tax-inclusive total.
Pre-tax price
—
- Tax included: —
- Rate used: —
On this page
Quick summary: Find the pre-tax price and tax amount from a tax-inclusive total. Enter the requested values, calculate, review the result, and compare more than one realistic scenario before making a decision.
Read the complete guide
What this calculator does
The Reverse Sales Tax Calculator estimates the pre-tax price and tax portion when you already know a tax-inclusive total.
How to use the calculator step by step
Enter the final price including tax and the applicable sales-tax rate. Use the rate that actually applies to the transaction.
How the calculation works
Pre-tax price equals tax-inclusive total divided by one plus the tax rate. Tax amount equals the total minus the pre-tax price.
Worked example and scenario testing
If the final total is 108.25 and the sales-tax rate is 8.25%, the pre-tax price is 100 and the included tax is 8.25.
How to interpret your result
Reverse tax calculation is not the same as simply subtracting the tax percentage from the final total because the tax percentage was originally applied to the smaller pre-tax base.
Accuracy, assumptions, and limitations
Different items may be taxed at different rates or be exempt, so a single-rate reverse calculation may not reproduce a mixed receipt.
Common mistakes to avoid
Do not multiply the gross total by the tax rate to extract included tax. That overstates the tax portion.
Privacy and browser-based calculations
Only total price and tax rate are processed. No payment information is required.