US sales tax formula and examples
Enter the pretax price and a verified combined tax percentage. Tax = pretax price × rate ÷ 100; total = pretax price + tax. A $100 purchase at an illustrative 8.25% produces $8.25 tax and $108.25 total. At 7.5%, a $80 purchase produces $6.00 tax and a $86.00 total.
Where to find an applicable tax rate
There is no single nationwide US sales tax rate. Taxable products, exemptions, state, county and city rules differ; consult official revenue agencies before entering a percentage. USAGov lists ways to find state and local tax agencies. Do not add a state rate to an already combined state-and-local rate.
What this calculator cannot determine
It cannot look up jurisdictions or establish taxability, shipping rules, seller obligations, exemptions or special tax rounding. It only performs arithmetic on your inputs. For a discounted pretax price use the discount calculator; for other percentage questions use the percentage calculator.
Additional example and FAQs
Sales tax in the United States is not a single nationwide rate. State, county, city, district, product category, exemptions and remote-seller rules can matter. Formula: sales tax = pretax amount × entered rate / 100; total = pretax amount + sales tax.
Example: a $100 purchase at an illustrative 8.25% combined rate generates $8.25 in tax and a $108.25 total. The rate is an example, not a suggested rate for any jurisdiction. Confirm the actual rate and taxable basis with authoritative local guidance.
Frequently asked questions
Does this determine the correct state and local tax rate?
No. You must find and enter the correct combined rate from an official source.
Is 8.25% the standard US rate?
No. It is only a worked example, not a nationwide rate.
Reverse sales tax: remove tax from a total
Switch the calculator to Remove sales tax from total when you know the tax-inclusive amount and the tax rate. The formula is pretax amount = total ÷ (1 + rate ÷ 100); the tax amount is the difference between total and pretax amount. At 8.25%, a total of $108.25 contains $100.00 pretax and $8.25 sales tax, before considering jurisdiction-specific rounding or product exemptions.
Use only a rate you have verified for the applicable location, sale and product. This calculation does not determine whether a purchase is taxable, perform a ZIP-code lookup or handle fees that are not part of the sales-tax percentage.