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Reverse Sales Tax Calculator

Working backward gives the price before tax and the tax that was included. $107.25 at 7.25% came from a $100 item with $7.25 of tax. Subtracting 7.25% of the total would give the wrong answer, which is a common mistake. It is useful when you need the pre-tax amount for expense reports, business bookkeeping, or checking a receipt.

Reverse Sales Tax Calculator: inputs

Calculated result
Price before tax$100
Tax included in the total$7.25

Reverse Sales Tax Calculator: Sales tax rate sensitivity

Reverse Sales Tax Calculator: Sales tax rate and Price before tax5 calculations vary the “Sales tax rate” input while holding the other entered inputs constant.5.3%$1026.3%$1017.3%$1008.3%$999.3%$98

The result is exact only when a single rate applied to the whole total. Items taxed at different rates, tips and non-taxable fees break it. Some states tax delivery or service charges and others do not.

Rounding at the line-item level can shift the total by a cent or two.

Reverse Sales Tax: worked example

Total paid including tax$107
Sales tax rate7.3%
Price before tax$100
Tax included in the total$7.25

Reverse Sales Tax: formula

Price before tax = total ÷ (1 + tax rate); tax = total − price before tax

OpenStax Prealgebra: percent applications

Total paid including tax is the amount on your receipt or invoice, and the sales tax rate is the combined rate that applied to the sale. Use the rate for the location where the sale was taxed, since state, county and city rates combine. If the total includes non-taxable items, such as food in some states, split them out first.

The math divides the total by one plus the rate, rather than subtracting the rate from the total.

Common error: Multiplying the total by the tax rate to find the tax. The rate applies to the pre-tax price, so it must be divided out of the total.

Reverse Sales Tax: changing Sales tax rate

Sales tax ratePrice before taxTax included in the total
5.3%$102$5.35
6.3%$101$6.31
7.3% (example)$100$7.25
8.3%$99$8.17
9.3%$98$9.08

Reverse Sales Tax: compare input ranges

InputTested fromToPrice before tax: low inputPrice before tax: high inputSwing
Total paid including tax$97$118$90$110$20 (20%)
Sales tax rate6.3%8.3%$101$99$1.86 (1.9%)

Reverse Sales Tax: individual input comparisons

InputValuePrice before taxTax included in the total
Total paid including tax$86$80$5.81
$97$90$6.56
$107$100$7.23
$118$110$7.98
$129$120$8.72
Sales tax rate5.3%$102$5.35
6.3%$101$6.31
7.3%$100$7.25
8.3%$99$8.17
9.3%$98$9.08

Reverse Sales Tax: combined input changes

Sales tax rate / Total paid including tax$86$107$129
5.3%$82$102$123
6.3%$81$101$121
7.3%$80$100$120
8.3%$79$99$119
9.3%$79$98$118

Reverse Sales Tax: which assumptions move the result?

Reverse Sales Tax: Price before tax as Total paid including tax changesPrice before tax starts at $80. Moving Total paid including tax from $86 to $129 changes it to $120, with Sales tax rate 7.3% kept fixed.$86$80$97$90$107$100$118$110$129$120
Chart quantityDisplayed settings
Total paid including tax$86 → $129
Price before tax$80 → $120
Sales tax rate7.3%
Reverse Sales Tax: Price before tax as Sales tax rate changesPrice before tax starts at $102. Moving Sales tax rate from 5.3% to 9.3% changes it to $98, with Total paid including tax $107 kept fixed.5.3%$1026.3%$1017.3%$1008.3%$999.3%$98
Chart quantityDisplayed settings
Sales tax rate5.3% → 9.3%
Price before tax$102 → $98
Total paid including tax$107

Reverse Sales Tax: values and definitions

Quantity and definitionValue used
Total paid including tax$107
Sales tax rate7.3%
Price before tax$100
Tax included in the total$7.25

Reverse Sales Tax: half and double Total paid including tax

Total paid including taxPrice before tax
$54$50
$107$100
$215$200

Taxes & Paycheck calculators: Gross Pay Calculator, PTO Accrual Calculator, 2026 Federal Income Tax Calculator, Take-Home Pay Calculator, Self-Employment Tax Calculator, Capital Gains Tax Calculator.

Tax is added on top of the price, so it cannot be backed out by subtracting the rate from the total. It has to be divided out. A $107.25 receipt at 7.25 percent came from a $100.00 price plus $7.25 of tax.

Taking 7.25 percent of the total instead gives $7.78 and a price of $99.47, which is wrong by more than 50 cents, and the error grows on bigger purchases.

Confirm the rate that applied at the register. State, county and city rates stack, and some items are taxed at a different rate or not at all.

Go forward from a price with the sales tax calculator, and check discounts with the percentage calculator. The car sales tax and fees calculator handles vehicle purchases with trade-in credits. Businesses can use it to separate collected tax from revenue on reports.

Can the total include a tip or separately taxed item?

Separate amounts on different tax bases first. Dividing a mixed receipt by one rate does not reconstruct each line’s pretax value or determine local tax treatment.

How do I find the price before tax?

Divide the total by one plus the tax rate as a decimal. For a 7.25% rate, divide by 1.0725, and the difference is the tax.

Why not just subtract the tax rate from the total?

Because the tax was charged on the pre-tax price, not on the total. Subtracting 7.25% of the total removes too much and understates the price.

Does this work with tips?

Use the total attributable to the price and tax being reversed. A gratuity, service charge or other amount may have jurisdiction-specific tax treatment. Do not assume every tip is untaxed; separate charges using the receipt and applicable rules before applying a single reverse-tax rate.