Sales Tax Calculator
This sales tax calculator helps you add sales tax to a price or back the tax out of a total you already paid. Enter the combined rate that applies to your purchase — your calculator does not look up rates by location — and switch between "add tax" and "find tax in a total" modes to instantly see the tax amount, pre-tax price, and final total.
Your purchase details
Choose a mode, then fill in the price (or total) and the tax rate.
What sales tax is and how it's calculated
Sales tax is a percentage-based charge that most US states — and often their counties and cities on top — add to the price of goods and many services at the moment of sale. The seller collects it from the customer and periodically remits it to the relevant tax authorities, which is why a receipt usually shows a subtotal, a separate tax line, and a final total. Combined rates are a patchwork: a state rate, layered with optional county and city rates, can land anywhere from roughly 0% in places with no sales tax to over 11% in some high-tax cities — and they can change whenever a government adjusts them. Because of that variability, this calculator does not attempt to guess your rate; you supply the combined percentage that applies to your purchase, and it handles the arithmetic.
The formulas this calculator uses
In "Add tax to a price" mode, starting from a known pre-tax price:
tax = price × (rate ÷ 100)
total = price + tax
In "Find tax in a total" mode, starting from a tax-included total, the calculator works backwards to separate the pre-tax price from the tax that's already baked into it:
pre-tax price = total ÷ (1 + rate ÷ 100)
tax = total − pre-tax price
Both directions use the same simple percentage relationship — the reverse mode just solves the same equation for a different unknown, which is exactly what you need when you only have a final, tax-inclusive number to work from (a receipt total, an invoice line, or a sticker price that already includes tax).
Worked example — an $80 item at a 7.25% rate
Say you're buying an item priced at $80 before tax, and the combined state-plus-local rate where you're shopping is 7.25%. The tax amount is $80 × (7.25 ÷ 100) = $80 × 0.0725 = $5.80, and the final total you'll pay at the register is $80 + $5.80 = $85.80. Now flip it around: if your receipt instead showed a tax-included total of $85.80 at that same 7.25% rate, "Find tax in a total" mode would divide $85.80 by 1.0725 to recover the $80.00 pre-tax price, then subtract to show the same $5.80 of tax — confirming the two modes are mirror images of the same calculation. Try both directions in the calculator above with your own numbers and combined rate.
Things to keep in mind
- Rates vary enormously by location. Five states — Alaska, Delaware, Montana, New Hampshire, and Oregon — charge no statewide sales tax, while most others combine a state rate with optional county and city rates that push the effective total well into the high single digits or beyond in some cities. Always use the exact combined rate for the specific address where the sale happens.
- Many everyday items are exempt or taxed differently. Groceries, prescription medicine, and sometimes clothing are commonly exempt or taxed at a reduced rate in many states, but the precise rules differ from place to place — check your state's official guidance rather than assuming.
- Sales tax isn't the same as VAT or GST. US sales tax is generally collected once, at the final retail sale, while value-added tax and goods-and-services tax systems used elsewhere collect incrementally at each stage of production with businesses reclaiming what they paid on inputs.
- This tool does not look up rates for you. It performs the percentage arithmetic on whatever rate you enter — it cannot account for your specific address, product-category exemptions, or rounding conventions used by a particular point-of-sale system.
Disclaimer
This calculator provides an estimate only, based solely on the price (or total) and tax rate you provide — it is not a location-based rate lookup, a point-of-sale system, or tax advice. Actual amounts charged at checkout may differ slightly due to jurisdiction-specific rounding rules, special category rates, or a combined rate that differs from what you entered. For pricing, filing, or compliance decisions, verify the exact rate and any applicable exemptions with your state's department of revenue or a qualified tax professional.
Frequently asked questions
- What is sales tax and who actually pays it?
- Sales tax is a percentage-based fee that US state and local governments add to the price of most goods and many services at the point of sale. The customer pays it as part of the final bill, and the seller collects it and remits it to the relevant tax authorities — the business is essentially acting as a collection agent, not the one bearing the cost.
- Why can’t this calculator just look up my local sales tax rate?
- Combined sales tax rates in the US are a patchwork of state, county, city, and sometimes special-district rates layered on top of each other, and they change over time as governments adjust them. Rather than risk showing you an outdated or mismatched figure, this tool lets you enter the exact combined rate you already know applies to your purchase and does the arithmetic instantly.
- How do I calculate sales tax on a purchase?
- Multiply the pre-tax price by the tax rate expressed as a decimal (divide the percentage by 100), then add that amount to the original price to get the total. For example, an $80 item taxed at 7.25% incurs $80 × 0.0725 = $5.80 in tax, for a total of $85.80 — exactly the calculation the "Add tax to a price" mode performs for you.
- How do I find out how much tax is included in a total I already paid?
- Switch to the "Find tax in a total" mode, enter the tax-included total and the rate, and the calculator divides the total by (1 + rate ÷ 100) to back out the pre-tax price, then subtracts that from the total to reveal the tax portion. This reverse calculation is useful for receipts, invoices, or any time you only know the final amount charged.
- Do all US states charge sales tax?
- No. Five states — Alaska, Delaware, Montana, New Hampshire, and Oregon — have no statewide sales tax, although Alaska does allow local jurisdictions to levy their own. Every other state charges a statewide rate, and most also allow counties and cities to add their own local rates on top, which is why combined totals vary so widely from one address to the next.
- Are any goods or services exempt from sales tax?
- Many states exempt or reduce the rate on everyday essentials such as groceries, prescription medicine, and sometimes clothing, though the precise rules differ from state to state and even between cities within the same state. Always check your state department of revenue’s exemption list before assuming an item is taxable or tax-free.
- Is sales tax the same as VAT or GST?
- They are related but structurally different consumption taxes. US sales tax is generally collected only once, at the final retail sale to the consumer, whereas value-added tax (VAT) and goods and services tax (GST) — used in most other countries — are collected incrementally at each stage of production and distribution, with businesses reclaiming the tax they paid on inputs. If you need to model VAT or GST specifically, look for a dedicated calculator for that tax type.
- How can businesses use this calculator for pricing?
- Retailers and service providers can use the "Add tax to a price" mode to quickly quote a tax-inclusive total for a customer, or the "Find tax in a total" mode to reverse-engineer the pre-tax price and tax collected from a tax-inclusive sticker price — handy for bookkeeping, receipts, or verifying that a point-of-sale system applied the expected rate.
- Why might my receipt show a slightly different tax amount than this calculator?
- Small differences usually come down to rounding rules (some jurisdictions round each line item rather than the total), a combined rate that differs slightly from what you entered, or special category rates for certain goods. This calculator applies straightforward percentage arithmetic to whatever single rate you provide, so it will not reproduce jurisdiction-specific rounding quirks exactly.
- Is this calculator a substitute for tax advice or an official rate lookup?
- No. It is a simple arithmetic estimator that applies the rate you enter — it does not look up rates by address, account for product-category exemptions, or constitute tax advice. For filing, pricing, or compliance decisions, verify the exact combined rate and any exemptions with your state’s department of revenue or a qualified tax professional.