Sales Tax Exactness,
No Surprise Surcharges.
Free sales tax calculators: add tax by state, reverse it out of a tax-included price, total vehicle purchase tax, and decode tax-included tags.
State + Local Combined Rates
Accounts for county and municipal add-ons where total rates reach 9%–10%.
Reverse Tax Math
Extract pure pre-tax price from receipt totals: Total ÷ (1 + Tax Rate) = Base Price.
Vehicle Sales Tax & Trade-In Credit
Many states tax only the difference between new car price and trade-in value.
SalesTaxMap Calculators
Sales Tax Calculator (by state)
Add your state's combined rate to any price — with the combined rate for every state built in.
Reverse Sales Tax Calculator
Pull the tax back out of a tax-included total — the pre-tax price, the tax line, and the rate that was applied.
Vehicle Purchase Tax & Fee Calculator
The out-the-door math for a car: sales tax on price minus trade-in, plus title, registration, and dealer fees.
Tax-Included Price Decoder
For tax-included tags (and travel): what the pre-tax price is, what the tax is, and what the same item costs to make.
Strategic Money Guides
A field guide to US sales tax: why your rate is never the state rate
State + county + city + districts: how stacked rates work and how to find your true combined rate in a minute.
Reverse tax math: the one calculation everyone does wrong
Divide, don't subtract — with the worked example that makes it stick.
12 mistakes people make with sales tax
The recurring errors we see in sales tax — what causes each one, and the habit that prevents it.