Sales Tax Calculator

Two modes in one: add tax to a pre-tax price, or enter a total including tax to find the pre-tax amount and the tax taken.

Fill either top pair or bottom pair, then press Calculate

Pre-tax price	$
Tax rate	%
Total including tax (reverse)	$

Result

Your result will appear here.

How it works

To add tax, multiply by (1 + rate/100). To go backwards from a total that already includes tax, divide by (1 + rate/100) to get the pre-tax price; the difference is tax.

Formula

Total = pre-tax × (1 + tax% ÷ 100)

Pre-tax = total ÷ (1 + tax% ÷ 100)

Tax = total − pre-tax

Worked example

$100 at 8% tax gives $108 total. If the receipt says $108 including 8% tax, the pre-tax price was $100 and tax was $8.

Assumptions

Assumes tax is a single percentage applied to the taxable amount. Some jurisdictions tax differently by category; this is a general calculation.

Reading the result

Use reverse calculation to compare prices across states/regions or to check if a listed total already includes tax.

For general information only. Tax rates and rules vary by jurisdiction.

How to use the Sales Tax Calculator

It takes a few seconds, and every figure is calculated in your browser.

Enter the pre-tax price.
Enter the tax rate.
Enter the total including tax if you are working backwards.
Press Calculate — the result appears in the dark panel beside the form.
Use Copy, CSV, Share or Print under the result if you want to keep it.