Sales Tax Calculator

How It Works

Sales tax in the United States is not one national rate — it is a patchwork of state and local rates that stack on top of each other. Forty-five states levy a state-level sales tax, and 38 states also allow local sales taxes, so the rate you actually pay at the till is usually the state rate plus a city or county rate. This calculator handles both directions of the same arithmetic. To add tax, it multiplies the price by the rate: tax = price × rate, and the total is price + tax. To remove tax from a price that already includes it, it divides instead: price before tax = total ÷ (1 + rate), because the tax was charged on the smaller pre-tax figure, not on the total you see.

That second direction trips people up. If a price including 10% tax is $110, the tax is not $11 — it is $10, because $100 × 1.10 = $110. Taking 10% off the total gives $99, which is wrong. Dividing by 1.10 gives the correct $100 pre-tax price and $10 of tax. The same logic applies at any rate, and it matters whenever you need to separate tax from a receipt total, claim a business expense, or check whether a seller charged you correctly.

The state dropdown uses average combined rates from the Tax Foundation's midyear 2026 figures (rates as of July 1, 2026). These are population-weighted averages of state and local rates, which is why they are labelled averages: your exact local rate may differ, sometimes by a lot. A shopper in one part of a state can pay a noticeably different rate from a shopper in another part, because local add-ons vary by city and county. If you know your exact local rate — it is printed on most receipts — type it in directly and the calculator will use that instead.

Worked Example

A laptop costs $1,200 before tax in California, where the average combined rate is 9.03%. The sales tax is $1,200 × 0.0903 = $108.36, so the total at checkout is $1,308.36. Going the other way: if you paid $1,308.36 including tax at 9.03%, the pre-tax price is $1,308.36 ÷ 1.0903 = $1,200.00, and the tax included is $108.36. Both directions agree, because they are the same calculation run forwards and backwards.

The state you buy in changes the bill by more than most people expect. The same $1,200 laptop costs $1,200.00 in Oregon, Montana, New Hampshire or Delaware — states with no statewide sales tax and no local tax — but $1,321.56 in Louisiana at its 10.13% average combined rate, a difference of $121.56 on one purchase. That is why the state dropdown matters: a single national guess would be wrong almost everywhere.

Assumptions and What This Calculator Leaves Out

• Rates in the dropdown are average combined rates (Tax Foundation midyear 2026, as of July 1, 2026) — your exact local rate may differ.
• The calculator assumes the whole price is taxable at one rate. In reality, many states exempt groceries, and some exempt or reduce the rate on clothing, medicine, or other goods.
• It does not model special local taxes, resort-area taxes, or the half-rate Urban Enterprise Zones in some New Jersey cities.
• It does not cover online purchases shipped across state lines, where the rate depends on the destination and the seller's nexus rules.
• Hawaii, New Mexico and South Dakota have broad-based taxes that reach many services, so their figures behave differently from a standard retail sales tax.

How much tax you pay on a $100 purchase at the rates in this calculator:

On a $100 purchase the gap between the cheapest and most expensive states is $10.13 — on a $1,000 purchase it is $101.30. For big-ticket items, the tax rate is a real part of the price comparison, not a rounding error.

How to Use This Calculator

Enter the price, then choose whether you want to add tax to it or remove tax from it. Pick your state from the dropdown to fill in its average combined rate automatically, or leave "Custom rate" selected and type any rate — for example, the exact rate printed on a receipt. The result updates as you type, showing the tax amount and the total (or the pre-tax price and the tax included) in a breakdown table. Use the Reset button to return to the California example.

Tips and Practical Advice

Always check the rate on your receipt before disputing a charge. The rate printed there is your exact local rate, and it is the number to use if you want an exact figure rather than the state average. If you are comparing prices between states for a big purchase — a laptop, furniture, a car — run the numbers with each state's average rate first; the difference can easily outweigh a small discount. And remember that the tax is charged on the price after any discount, so a sale price lowers the tax too: a 20% discount on a $1,200 item saves $240 on the price and another $21.67 of tax at 9.03%.

If you buy online, the rate that applies is generally the rate where the item is delivered, not where the seller is based — so use your own state's rate for online orders. And keep in mind that not everything is taxed: groceries are exempt in most states, and several states exempt clothing or tax it at a reduced rate, so a grocery bill will often come in well below what a flat-rate calculation suggests.

Sources: Tax Foundation, 2026 Sales Tax Rates, Midyear Update (rates as of July 1, 2026); US population-weighted average combined rate 7.53%. Last reviewed: 13 November 2026.

Frequently Asked Questions