Calciro

Reverse Sales Tax Calculator

Enter a total price that already includes sales tax and the applicable tax rate. The calculator will separate the total into the original pre-tax price and the sales tax amount.

Price Before Sales Tax
$100.00
Total Price Including Tax
108.25
Tax Multiplier
1.083
Sales Tax Included
$8.25

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The result shows the estimated price before sales tax was added. The calculation breakdown also shows the sales tax amount included in the total price.

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How to Use This Calculator

Enter the total price paid, including sales tax, and the combined sales tax rate. Use the full applicable rate, including both state and local sales taxes where relevant.

Formula & Methodology

Pre-tax price = Total price ÷ (1 + Sales tax rate ÷ 100). Sales tax amount = Total price − Pre-tax price.

Example: $108.25 Total at an 8.25% Sales Tax Rate

For a total price of $108.25 and a sales tax rate of 8.25%, the original pre-tax price is $100.00 and the included sales tax is $8.25.

This calculator assumes the entire entered total is subject to one combined sales tax rate. It does not account for tax-exempt items, multiple tax rates within one purchase, special district taxes, fees, discounts, tax holidays, product-specific taxes, cash-rounding rules, or jurisdiction-specific rounding methods.

This calculator is provided for general estimation and record-checking purposes only. It is not tax, accounting, or legal advice. Verify the applicable tax rate, taxable amount, exemptions, and rounding rules with the relevant state or local tax authority.

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Frequently Asked Questions

How do I calculate the price before sales tax?
Divide the total price including tax by one plus the sales tax rate expressed as a decimal. For example, divide by 1.0825 when the sales tax rate is 8.25%.
How do I find the sales tax included in a total?
First calculate the pre-tax price by dividing the total by one plus the tax rate. Then subtract the pre-tax price from the total.
What sales tax rate should I enter?
Enter the full combined rate that applied to the transaction, including state and local sales taxes where applicable.
Can I simply subtract the tax percentage from the total?
No. Subtracting the tax percentage directly from a tax-inclusive total produces an incorrect result because the percentage was originally applied to the smaller pre-tax price.
Does this calculator work for any U.S. state?
Yes, provided you enter the correct combined sales tax rate for the transaction. The calculator does not automatically look up state or local rates.
Does the calculator include local sales tax?
It includes local tax only when you enter a combined rate that already contains the applicable state and local components.
Why might my receipt differ by one cent?
Small differences can result from merchant, state, or local rounding rules and from whether tax was calculated per item or on the entire transaction.

Last updated 7/15/2026