Sales Tax Calculator
Add or remove US sales tax from any amount and see the tax and pre-tax price instantly.
The sales tax calculator adds US sales tax to a price, or works backwards to find the pre-tax price hidden inside a total. Because rates differ by state, county and city, the calculator takes whatever combined rate you enter.
How to use the calculator
- Enter the amount you are working with.
- Enter the combined sales tax rate for your location.
- Choose whether to add tax to a pre-tax price or remove it from a total.
- The result shows the total, the tax and the pre-tax price.
How it is calculated
Remove tax: Pre-tax = Total ÷ (1 + rate ÷ 100) · Tax = Total − Pre-tax
Worked example
$100 at 8.25% sales tax
Tax = $8.25 and the total is $108.25
Reverse it: a $108.25 total is $100 before tax.
Who should use this calculator
- US shoppers checking what a listed price will actually cost at the register.
- Small businesses and online sellers working out the tax to add to an invoice for a specific location.
- Anyone reverse-calculating the pre-tax amount from a receipt to expense or record it correctly.
- Sellers checking whether sales tax applies to a discounted or bundled transaction.
Common mistakes to avoid
- Using only the state rate. Most US sales tax is a combined rate that includes county, city and sometimes special district taxes. The difference between a 4% state rate and an 8.25% combined rate is substantial.
- Assuming a no-tax state means no tax at all. Five states have no statewide sales tax, but local taxes can still apply in parts of Alaska and elsewhere.
- Applying one rate across different states. Once you have nexus in more than one state, the rate depends on where the buyer is, not where you are.
- Getting the direction wrong. If a receipt total already includes tax, divide by one plus the rate rather than subtracting the rate from the total.
- Ignoring which items are exempt. Groceries, prescription medicine and some clothing are exempt in many states, so a single blanket rate can be wrong for a mixed basket.
Inclusive and exclusive, and why it matters
A $100 item at an 8.25% sales tax becomes $108.25 — tax of $8.25 added on top. Working backwards is where people slip: to remove tax from $108.25 you divide by 1.0825, giving $100. Subtracting 8.25% instead gives $99.32, which understates the pre-tax value and misstates the tax on every line of an invoice.
Two other details matter for sellers. Shipping is taxable in some states and not others, and a trade discount is normally applied before tax is calculated. When a receipt looks slightly off, checking whether the tax was applied to the right base explains most discrepancies.
Sales tax terms explained
- Combined rate
- The total of state, county, city and district sales taxes that applies at the point of sale.
- Nexus
- The connection that obliges a seller to collect sales tax in a state — a physical presence or enough sales volume.
- Use tax
- Tax owed on purchases where sales tax was not collected, usually paid by the buyer directly to the state.
- Resale certificate
- A document that lets a business buy goods for resale without paying sales tax.
- Taxable base
- The amount sales tax is calculated on, after discounts and before tax.
Getting the rate right for a location
Sales tax is set by where the sale happens, not where the seller sits. Two addresses a few miles apart can have different combined rates because county, city and special district taxes differ. For a single invoice, look up the rate by the buyer's ZIP code and record which rate you applied, so the calculation can be explained if it is ever queried.
For a business selling across several states, keeping rates current by hand does not scale. Most sellers use address-based tax software that updates rates automatically and stores the rate used for each transaction, which becomes valuable evidence during an audit.
Frequently asked questions
Which states have no sales tax?
Five states have no statewide sales tax: Alaska, Delaware, Montana, New Hampshire and Oregon. Local taxes may still apply in parts of Alaska.
How do I reverse sales tax out of a total?
Divide the total by (1 + rate ÷ 100). For an 8.25% rate, divide by 1.0825. The difference between the total and the result is the tax.
Are groceries taxed?
It depends on the state. Most states exempt unprepared groceries but tax prepared food, and some cities add their own food taxes. Check your state revenue department for the current rules.