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Reverse Sales Tax Calculator

Work backwards from a total receipt price to instantly find the original pre-tax amount and the exact sales tax paid.

Receipt Details

$

The final amount paid on the receipt.

%

The percentage of tax applied in your area.

Price Breakdown

Enter your total amount and tax rate to see the pre-tax breakdown.

How Do You Calculate Reverse Sales Tax?

Often, you are handed a receipt that only shows the final, bottom-line total you paid, completely obscuring how much of that total was actually sales tax. A reverse sales tax calculation allows you to "back out" the tax to find the original, pre-tax base price of the item or service.

This is an incredibly common necessity for accountants, small business owners, and employees filling out expense reports. If you are doing larger financial planning, be sure to check out our other Business Calculators to keep your finances perfectly balanced.

The Mathematical Formula

You cannot simply multiply the total by the tax rate and subtract it. That will result in an incorrect number. The proper formula for finding the pre-tax amount is:

Pre-Tax Price = Total Price รท (1 + Tax Rate)

For example, if you paid $105.00 total and your local tax rate is 5%, you convert the 5% to a decimal (0.05). You then divide $105.00 by 1.05, resulting in exactly $100.00.

Why is this useful?

Reverse tax calculation is a vital part of bookkeeping for several reasons:

  • Expense Reporting: Many corporate accounting departments require employees to separate base costs from tax paid.
  • Tax Returns: If your business operates in a region that allows you to claim back sales tax (like VAT in Europe or GST in Canada), you must know exactly how much tax was collected on your purchases.
  • Pricing Strategy: If you want to sell an item for exactly $20.00 "out the door" (including tax), this formula helps you set the correct shelf price.