Sales Tax by County API
Look up county-level sales tax rates using FIPS codes for unambiguous jurisdiction identification. Every county in the US, normalized and accessible via a single REST endpoint.
What Are FIPS Codes?
FIPS codes (Federal Information Processing Standard) are unique numeric identifiers assigned to every county and county-equivalent in the United States by the US Census Bureau.
FIPS Code Structure
Unlike county names, FIPS codes are never ambiguous. There are 31 counties named “Washington” in the US, but each has a unique FIPS code. This makes FIPS the preferred identifier for tax data systems.
Why County-Level Data Matters
In most US states, the county is the primary sub-state tax jurisdiction. Counties levy their own sales tax rates that stack on top of the state rate. Getting the county wrong means applying the wrong rate.
Tax Remittance
Businesses must remit collected county taxes to the correct county. Accurate FIPS mapping ensures you report to the right jurisdiction.
Audit Defense
Tax auditors verify that the correct county rate was applied. FIPS-based lookups provide an audit trail that ties rates to specific jurisdictions.
Multi-State Compliance
Ecommerce businesses with nexus in multiple states need county-level precision for every destination. A normalized API handles this complexity.
Reporting
Generate accurate tax liability reports grouped by county. FIPS codes make it easy to aggregate and reconcile data.
Example County Lookup
curl -H "Authorization: Bearer YOUR_API_KEY" \
"https://salestaxapi.io/api/rates?state=TX&zip=77001"{
"success": true,
"data": {
"state": "TX",
"zip": "77001",
"total_rate": 0.0825,
"breakdown": {
"state_rate": 0.0625,
"county_rate": 0,
"city_rate": 0.02,
"district_rate": 0
},
"county": "Harris County",
"county_fips": "48201",
"last_updated": "2026-01-15"
}
}Explore State-Level Rates
Get county-level precision today
Access FIPS-normalized county tax rates across all 50 states with a free API key.
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