Free Tax Tool

Reverse Sales Tax Calculator

Enter the total you paid and the sales tax rate to find the price before tax and how much of the total was tax. Or switch modes to add tax to a price.

$

The amount on the receipt or card statement

%

Combined state and local rate, from the receipt or your state revenue department

Sales tax backed out of the total

Price before tax

$100.00

Price before tax
$100.00
Sales tax (8.25%)
$8.25
Total price with tax
$108.25
Tax as a share of the total
7.62%

Pre-tax price = total / (1 + tax rate), rounded to the cent. Stores round tax per item or per receipt, so your receipt can differ by a cent or two.

How reverse sales tax is calculated

Sales tax is charged as a percentage of the pre-tax price, so the total you pay is the price times (1 + tax rate). To work backwards, divide instead of multiply:

  1. Convert the rate to a decimal: 8.25% becomes 0.0825.
  2. Price before tax = total / (1 + rate). Round to the cent.
  3. Sales tax = total - price before tax.

Example: you paid $108.25 at a combined 8.25% rate. $108.25 / 1.0825 = $100.00 before tax, so $8.25 of the total was sales tax. That is 8.25% of the price but only 7.62% of the total, which is why taking 8.25% off the total gives the wrong answer.

This tool does not use a table of state rates, because city, county, and district add-ons make the combined rate different from place to place. Use the rate on your receipt or look it up with your state revenue department. Once you have the pre-tax cost, the markup calculator and profit margin calculator help you price what you resell, and the expense report generator can log the split for reimbursement. If you are adding up sales tax to deduct, compare your itemized total with the standard deduction calculator first.

Frequently asked questions

How do you calculate sales tax backwards?

Divide the total you paid by 1 plus the tax rate as a decimal. That gives the price before tax. Subtract it from the total to get the tax. For example, $108.25 paid at an 8.25% rate is $108.25 / 1.0825 = $100.00 before tax, so the tax was $8.25.

What is the formula for the price before tax?

Price before tax = total price / (1 + tax rate). Sales tax = total price - price before tax. Convert the rate to a decimal first, so 8.25% becomes 0.0825 and the divisor is 1.0825.

Why can’t I just take the tax rate off the total?

Sales tax is a percentage of the pre-tax price, not of the total. Taking 8.25% of a $108.25 total gives $8.93, which overstates the tax by 68 cents and puts the pre-tax price at $99.32 instead of $100.00. The error grows with the rate and the size of the purchase, so always divide by 1 plus the rate.

Is sales tax deductible?

For personal purchases, you can deduct state and local general sales taxes only if you itemize on Schedule A, and you must choose either sales taxes or state and local income taxes, not both. The deduction is part of the state and local tax (SALT) deduction, which for 2026 is capped at $40,400 ($20,200 married filing separately) and reduced at higher incomes. For a business, sales tax paid on purchases is part of the cost of the item or expense.

What is a combined sales tax rate?

Most purchases are taxed by the state plus one or more local governments, such as a county, city, or special district. The combined rate is the total of all of them, and it is the rate you should use in this calculator. Combined rates vary from city to city and even between neighboring addresses, so check your receipt or your state revenue department’s rate lookup.

How do I back out sales tax for an expense report or bookkeeping?

Enter the receipt total and the combined rate to split it into the pre-tax amount and the tax. Many bookkeeping systems record the two separately, for example to track sales tax paid, to claim a refund of foreign VAT, or when a reimbursement policy excludes tax. If the receipt shows the tax on its own line, use that exact figure, since stores round per item.

Does this work for VAT and GST?

Yes. Value added tax and goods and services tax are also usually included in the shelf price, so the same formula backs them out: divide the price by 1 plus the VAT or GST rate.

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