A worked example
A $100 item at an 8% combined sales tax rate adds $8.00 in tax, for a total of $108.00. Switch to reverse mode and enter $108.00 as the total at the same 8% rate, and it correctly pulls out $100.00 as the pre-tax price — not $99.36, which is what simply subtracting 8% of the total would (incorrectly) give.
Frequently asked questions
Why isn't there a built-in rate for my state or city?
Combined sales tax rates in the US alone vary across more than 11,000 local jurisdictions — state, county and city rates stack differently almost everywhere. Rather than risk showing you a stale or wrong number, this calculator asks for the combined rate you already know applies, and does the math instantly.
What's the difference between the two modes?
"Add tax to price" starts from a pre-tax price and adds tax on top — useful when pricing something out before checkout. "Extract tax from total" works backward from a final receipt total to show what the pre-tax price and tax amount actually were.
Why can't I just subtract the tax rate from the total to reverse it?
Because the tax rate applies to the pre-tax price, not the total — subtracting it from the total overstates the tax removed. The correct reverse calculation divides the total by (1 + rate) first, which is what this calculator does for you.
This calculator provides general estimates only. Confirm your jurisdiction's exact combined sales tax rate with a local source before relying on this for accounting or filing purposes.