Reverse-calculate sales tax: enter a tax-included total to find the pre-tax price and tax amount, or solve for the tax rate. Includes US state rates.
Tap an example to autofill the calculator.
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Sometimes you have the final, tax-included price and need to work out the original price before tax — for an expense report, a bookkeeping reconciliation, or simply to see how much tax you paid. That's a reverse sales tax calculation. Instead of adding tax to a price, you divide the total by 1 plus the tax rate to recover the pre-tax amount, then subtract to find the tax. This calculator does it instantly: enter a tax-included total and the rate (or pick your US state to fill the rate automatically) to get the pre-tax price and the exact tax, or switch modes to find the rate from a price and total.
A reverse sales tax calculator — sometimes called a sales tax decalculator — works backward from a tax-included total to find the original pre-tax price and the tax amount. A normal sales tax calculator starts with a price and adds tax; this one starts with the final total and removes the tax. It's the tool you need when the tax is already baked into the number you have, such as a receipt total or an all-in price. Enter the total and the tax rate and it returns the pre-tax price and tax; or, if you know both the pre-tax price and the total, it can find the effective tax rate.
Formula
Separate the pre-tax amount and tax from an all-in receipt total for reimbursement.
Verify sales tax collected against totals when closing the books.
Figure out the tax on a receipt that only shows the final total.
Back out the base price from a tax-inclusive quote.
Confirm what tax rate you were actually charged on a purchase.
Compare how much of a total is tax under different state rates.
Get the original price from any tax-included total — essential for expense reports and reimbursements.
Don't know your exact rate? Choose your US state and the average combined rate fills in automatically.
Switch modes to work out the effective tax rate from a pre-tax price and a final total.
Get the precise tax amount that was included in the total, broken out clearly.
Every result shows the formula and each step, so you can check the work or learn the method.
Divide the tax-included total by 1 plus the tax rate (as a decimal) to get the pre-tax price, then subtract that from the total to find the tax. For example, with a $107 total and a 7% rate: $107 ÷ 1.07 = $100 pre-tax, and $107 − $100 = $7 in tax.
Use the formula price before tax = total ÷ (1 + tax rate). If a receipt shows $54.00 and the tax rate is 8%, the price before tax is $54 ÷ 1.08 = $50.00, meaning $4.00 was sales tax.
If you know both the pre-tax price and the final total, the tax rate is (total − pre-tax) ÷ pre-tax × 100. For example, $100 pre-tax and a $108 total give (108 − 100) ÷ 100 × 100 = 8%. Use this calculator's Find the tax rate mode to do it automatically.
It's a tool that works backward from a tax-included total to find the original pre-tax price and the tax amount — the opposite of a regular sales tax calculator, which adds tax to a price. It's useful when the tax is already included in the number you have.
Divide the total by 1 plus the tax rate. Removing 7% from $107 gives $107 ÷ 1.07 = $100, and the $7 difference is the sales tax. This is different from simply subtracting 7% of the total, which gives the wrong answer.
Five states have no statewide sales tax: Delaware, Montana, New Hampshire, Oregon, and Alaska (though Alaska allows local sales taxes). In those states, the pre-tax price equals the total unless a local tax applies.