How to use the sales tax calculator
Pick a mode, enter your numbers, and the breakdown appears instantly. In “add tax” mode, enter the pre-tax price and the rate to get the tax and the final total. In “remove tax” mode, enter a tax-inclusive total and the rate to recover the original price and the tax portion.
Why the reverse calculation trips people up
Adding tax is straightforward, but going the other way is where mistakes happen. A common error is subtracting the tax percentage directly from the total — but the percentage was never taken from the total, it was taken from the smaller pre-tax price. The correct method is to divide the total by one plus the rate. This tool handles that automatically, which makes it useful for expense reports, VAT extraction, and checking receipts.
Getting the rate right
The accuracy of the result depends entirely on the rate you enter. In many places the headline rate is actually a combination of state, county, and city taxes, so use the total combined rate for your location rather than a single component. Everything is calculated in your browser and nothing you enter is stored or sent anywhere.