Sales Tax Calculator
Pick a state, then a county or city, to calculate sales tax on a purchase using exact combined rates reviewed against official state sources. Rates come from the Sales Tax Atlas, Prophit.ai's source-linked guide to sales tax in all 50 states and the District of Columbia.
Choose a state and locality
How this calculator works, and where the rates come from
For the 13 states where Prophit.ai publishes local rates, this calculator uses the exact combined rate for the county or city you select — the state rate plus any county, city, or district rate that applies there. Every rate is reviewed against an official state revenue or tax authority source, with a visible reviewed date on each state and locality page.
For states outside that local tier, and for the five states with no statewide general sales tax, this page links to the full state guide instead of inventing a rate. Rates change on official schedules — always confirm the current rate and effective date against the linked source before filing.
Sales tax calculator FAQ
01How is a combined sales tax rate calculated?
A combined rate stacks the state sales tax rate with any local rates that apply where the sale is sourced — typically county, city, and sometimes special-purpose district rates. This calculator uses the exact combined rate published for the county or city you choose, not an estimate.
02Why do sales tax rates differ by city and county?
A state sets one statewide rate, but many states also let counties, cities, and special districts add their own local sales tax on top of it. Two addresses a few miles apart can sit in different counties or cities and owe different combined rates as a result.
03Is this calculator filing advice?
No. This tool estimates the tax on a purchase amount using a reviewed combined rate. Rates change on official schedules, so confirm the current rate and effective date against the official source linked on each state and locality page before filing a return.
04Which states have exact county and city rates in this calculator?
Prophit.ai publishes reviewed local (county and city) rates for 13 states so far, alongside guides for all 50 states and the District of Columbia. States without published local rates yet show a link to that state's sales tax guide instead of an estimated local rate.
05How often are the rates reviewed?
Every rate in this calculator is reviewed against an official state revenue or tax authority source, with a visible reviewed date shown on each state and locality page.
06What about states with no sales tax?
Oregon, New Hampshire, and Delaware have no state or local general sales tax. Alaska and Montana have no statewide sales tax, but local governments in those two states can still levy their own sales tax, so purchases there are not automatically tax-free.
- The tax content is published and auditable: the Sales Tax Atlas carries 51 state and DC guides and 3,800+ county and city rate pages, each pinned to its official source.
- Production standalone Sales Tax and Use Tax Engines ($99/month per location through sales-assisted setup, with 10,000 calls/month included) return determinations to source systems through an API.
