Reverse Sales Tax Calculator
Enter a total that already includes sales tax and your tax rate — the calculator works backward to the pre-tax price and the tax paid.
To remove sales tax from a total, divide the total by one plus the tax rate written as a decimal. The result is the pre-tax price; subtract it from the total to get the tax. Dividing by the rate alone, or subtracting the rate as a percentage of the total, both give the wrong answer.
⚠️ Double-check important results. This is an educational estimate, not professional advice — and where it uses a rate, bracket or fee, those change over time. Verify anything you'll rely on, especially in legal, financial, tax or medical matters, and read our full disclaimer. Think a result is wrong? Tell us so we can fix it.
How to Use This Calculator
Enter the total amount you actually paid — the figure on the receipt that already includes sales tax. Then enter your combined state and local sales tax rate. The rate field is pre-filled with a typical U.S. rate as a starting point, but sales tax varies widely by state and city, so replace it with your own rate for an exact answer.
The calculator instantly splits the total into the pre-tax price and the tax portion. This is useful for expense reports, bookkeeping, and checking that a receipt added tax correctly.
How the Calculation Works
Sales tax is added by multiplying the pre-tax price by one plus the rate. So a $100 item at 7% becomes 100 × 1.07 = $107. To reverse that, you undo the multiplication by dividing: 107 ÷ 1.07 = $100.
The common mistake is to take 7% of the total and subtract it. Seven percent of $107 is $7.49, which would leave $99.51 — wrong, because the tax was charged on the smaller pre-tax figure, not the total.
pre-tax price = total ÷ (1 + tax rate ÷ 100)
Worked Example
You paid $107.00 for an item and your combined sales tax rate is 7%. Divide the total by 1.07: 107 ÷ 1.07 = $100.00. That is the pre-tax price.
The tax paid is the difference: 107 − 100 = $7.00. You can check it forward — $100 × 1.07 = $107 — which confirms the split.
What the Result Means
The pre-tax price is the figure you record as the actual cost of goods for accounting or reimbursement, and the tax amount is what you paid to the state and locality — often recorded separately or reclaimed by a business.
If the tax portion the calculator shows does not match the tax line on your receipt, the rate you entered probably differs from the rate that was actually charged, which can happen with special district taxes or tax-exempt items in the same order.
Assumptions, Limitations and Rate Source
This calculator assumes a single tax rate applied to the whole total. Orders that mix taxable and tax-exempt items, or that include separately taxed items, need to be split before using it.
Sales tax in the United States is set by each state and, in most states, additional local jurisdictions — there is no single national rate. Always confirm your exact combined rate with your state's Department of Revenue. The default rate below is a national reference point, not a legal figure for any specific location.
- Assumes one flat rate across the entire total
- Does not handle mixed taxable and exempt items in one order
- Your exact rate comes from your state and local tax authority
- Results are rounded to two decimal places
Rate source. The default value used above (7.0%) comes from Tax Foundation — State & Local Sales Tax Rates, 2025. Rates like this change over time, so the field in the calculator is editable — overwrite it if it has changed.
Last verified 2026-07-30
Who Uses a Reverse Sales Tax Calculator
Business owners, bookkeepers, and freelancers use this to back the tax out of a gross total, separating the pre-tax price from the sales tax on a receipt, invoice, or cash sale. It is invaluable at tax time for expense records, for pricing an item so the rounded total already includes tax, and for anyone reconciling receipts that show only the final amount. Enter the total and your local combined rate to split the two instantly.
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Frequently Asked Questions
How do I calculate the pre-tax price from a total?
Divide the total by one plus the tax rate as a decimal. At 7%, divide by 1.07. For a $107 total that gives $100 pre-tax, and the $7 difference is the tax.
Why can't I just subtract the tax percentage from the total?
Because the tax was calculated on the smaller pre-tax price, not the total. Subtracting the percentage of the total removes too much. Dividing by one plus the rate correctly reverses the original calculation.
What sales tax rate should I enter?
Your combined state and local rate for where the purchase was made. Rates range from 0% in a few states to over 10% in some cities, so look yours up with your state's Department of Revenue and overwrite the default.
Does the United States have one national sales tax rate?
No. There is no federal sales tax. Each state sets its own rate, and most allow county and city taxes on top, so the total rate depends on the exact location of the sale.
Can I use this to find how much tax I paid?
Yes. The calculator shows both the pre-tax price and the tax amount. The tax is simply the total minus the pre-tax price it calculates.
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