How Reverse Sales Tax Works
A complete guide to the reverse tax formula with real-world examples.
3 Simple Steps
Calculate your pre-tax price in seconds — no account required.
Enter the Total Price
Type in the full amount you paid — the price including tax that appears on your receipt or invoice.
Select or Enter the Tax Rate
Choose your US state for the combined rate, or enter any custom rate. You can also use our quick-select buttons for common rates.
Get Your Results Instantly
Click calculate and instantly see the original pre-tax price, the exact tax amount paid, and a complete breakdown.
The Mathematics Behind Reverse Tax
Why Not Just Subtract the Percentage?
A common mistake is to subtract the tax percentage directly from the total. For example, with a 7.5% tax on $107.50: some people calculate $107.50 × 7.5% = $8.0625 and subtract that, getting $99.44. This is wrong.
The correct answer is $100.00. The issue is that tax was calculated on the original price, not on the total. 7.5% of $100 = $7.50, so the total is $107.50. To reverse this, we divide.