Sales tax calculator
Calculate the sales tax on a purchase, the total with tax, and the pre-tax price if you only know the final amount.
US-style single-stage sales tax. Local rates and item exemptions vary.
How this calculator works
US sales tax is charged at the point of sale and is a percentage of the selling price. It is set by state, county and city governments, so the combined rate at one address can combine three or more layers: state, county, city and sometimes special district taxes. Five states have no statewide sales tax, and rates range from around 1.8% to over 11% in some cities.
Two practical uses for this calculator. First, working out what a purchase will actually cost after tax — add the local combined rate. Second, reverse-engineering the pre-tax price from a receipt total, which is handy for expense claims and budgeting, especially for items like groceries and prescription drugs that are often exempt. If an item is tax-exempt or taxed at a reduced rate in your area, use the effective rate that applies to that item rather than the general rate.
The formula
Tax = price × rate ÷ 100; total = price + tax. To go backwards from a tax-inclusive total T at rate r:
tax = price · r
total = price · (1 + r)
price = total / (1 + r)For example, a $108.25 total at 8.25% implies a pre-tax price of $100 and $8.25 of tax.
Worked example
A 100 purchase at a 8.25% combined sales-tax rate adds $8.25 of tax, for a total of $108.25. The effective combined rate on the purchase is 8.25%.
Common mistakes
- Using a state rate instead of the combined rate. The rate that applies at the register includes county and city taxes; look up the address-specific rate.
- Charging tax on exempt items. Many states exempt food, prescription drugs and some services. Tax-exempt purchases should use a 0% rate.
- Forgetting online marketplace rules. Marketplaces such as Amazon collect sales tax based on the delivery address, not the seller's home state.
Frequently asked questions
How do I calculate sales tax backwards?
Divide the tax-inclusive price by 1 + (rate ÷ 100). A $108.25 total at 8.25% becomes $100.00 before tax; the difference is the tax.
Which US states have no sales tax?
Alaska, Delaware, Montana, New Hampshire and Oregon have no statewide sales tax, though local taxes may apply in parts of Alaska and Montana.
Is sales tax the same as VAT?
No. Sales tax is collected once, at the final sale to the consumer. VAT and GST are collected at multiple stages along the supply chain with credits for tax already paid.
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