IRS Principal Business Activity (PBA) Codes

NAICS Sectors Directory — Full drill down list of 20 sectors.

EntityCodes.org

Authoritative directory for corporate entity registration formats, size classification standards, and industry concordance mappings.

Registry

Ask Jack — Smart Finder NAICS Directory SIC Directory Crosswalk Tool IRS Schedule C Codes Format Validators

Resources

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Official Sources

U.S. Census Bureau Small Business Administration Internal Revenue Service

Disclaimer: Reference only — verify with the official source. entitycodes.org is not affiliated with any government agency. No warranty and no liability. Primary data sourced from public-domain U.S. government records.

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Hi! I'm Jack. Describe your business in plain English (e.g. “I run a roofing LLC”) or type a code number — I'll return your exact NAICS & SIC code. 100% deterministic, no AI.