Sales Tax Calculator

How this is worked out

Adding tax is the easy direction: multiply the price by the rate and add it on. $100 at 9.03% is $9.03 of tax and $109.03 to pay.

Taking tax out is where people go wrong, and the arithmetic is not symmetric. To find the pre-tax price inside a tax-inclusive total you divide:

pre-tax = total ÷ (1 + rate)

Subtracting the percentage instead gives the wrong answer, and it is wrong in a way that looks plausible. Take 9.03% off $109.03 and you get $99.18, not $100. The reason is that the tax was calculated on the smaller number: $9.03 is 9.03% of the pre-tax price but only 8.28% of the total.

The error grows with the rate. At Louisiana's 10.13% combined rate, subtracting rather than dividing is out by about 1% of the total on every line — enough to matter on an invoice, and enough to fail a reconciliation.

The rate itself is the harder problem. The United States has no national sales tax; rates are set by states, counties, cities and special districts, and there are roughly 13,000 taxing jurisdictions. The state and average local figures here are the right tool for an estimate and the wrong one for an exact answer.

A worked example

The state rate is rarely the rate you pay

Alabama’s state rate is 4%, which sounds low until you add an average local rate of 5.46% and arrive at 9.46% — one of the highest combined rates in the country. Louisiana does the same thing more dramatically: a 5% state rate and a 5.13% average local rate, for a combined 10.13%.

The reverse also happens. Indiana, Kentucky, Maryland, Massachusetts, Michigan, Rhode Island, Connecticut and Maine have no local sales taxes at all, so the state rate is the whole story.

Alaska is the strangest case: no state sales tax whatsoever, but local rates that in some boroughs exceed 7%. It appears in "no sales tax" lists and residents of Juneau pay 5%. The table on this page shows both components so the distinction is visible.

Five states with no statewide sales tax

Delaware, Montana, New Hampshire and Oregon have no sales tax at any level. Alaska has no state rate but does have local ones. That is the whole list, and it is worth knowing which of the five is which before planning a purchase around it.

The money is raised elsewhere. Oregon has a comparatively high income tax; New Hampshire has among the highest property taxes in the country; Delaware levies a gross receipts tax on businesses that is passed through in prices. None of these states is simply cheaper.

Buying across a state line to avoid sales tax is also less effective than it sounds. Most states levy a use tax at the same rate on goods bought elsewhere and brought home, and while enforcement on small purchases is essentially nil, it is not on vehicles — which are taxed where they are registered, not where they are bought.

What is taxed differs as much as the rate does

Groceries are the clearest example. Most states exempt unprepared food entirely; a handful tax it at a reduced rate; a few tax it in full. Prepared food is usually taxed everywhere, which produces the well-known absurdities — a rotisserie chicken taxed and a cold one not, a bagel sliced and a bagel whole.

Clothing is exempt in Pennsylvania, Minnesota and New Jersey, exempt below a price threshold in Massachusetts, Rhode Island and New York, and fully taxed elsewhere. Prescription drugs are exempt almost everywhere; over-the-counter medicine usually is not.

Several states also run sales tax holidays, typically for a weekend before the school year. This calculator applies a single rate to whatever you enter — it does not know whether the item is exempt, and no calculator reliably can.

Working backwards from a receipt

This is the direction most people need and the one most calculators handle badly. If you have a total and need the pre-tax amount — for an expense claim, a reimbursement, or bookkeeping — divide by one plus the rate.

A useful sanity check: the tax as a share of the total is always smaller than the rate. At a 9.03% rate the tax is 8.28% of the total. If your extracted tax comes out at exactly 9.03% of the total, you subtracted instead of dividing.

Switch the direction above and the calculator shows the working, including what the wrong method would have given, so the difference is visible rather than asserted.

Assumptions and sources

State and average local rates

Tax Foundation, "State and Local Sales Tax Rates, Midyear 2026". Local figures are population-weighted averages. checked 2026-08

Extraction formula

pre-tax = total ÷ (1 + rate). Verified in tools/test/payroll.mjs against a round-trip on every published rate.

Not included

Which goods are exempt in your state, sales tax holidays, special district rates, and use tax on out-of-state purchases.