Verified conversions, never guesses.
Converting a code between classification systems is easy to do badly — many sites match by number or by fuzzy text and silently mislabel businesses. Every mapping on IndustryCodes carries an evidence source (hover any exact/approximate badge to see it), resolves through at most two verified hops, and is labeled by its weakest hop. When no verified mapping exists, we say so instead of guessing.
Official correspondence tables
UN Statistics Division (ISIC Rev 4 ↔ Rev 5), US Census Bureau (ISIC ↔ NAICS 2022) and the Australian Bureau of Statistics (ANZSIC ↔ ISIC) publish authoritative mappings. We compose them conservatively: a result is only "exact" when every hop is exact.
Exact code identity
NAICS is maintained trilaterally: where the US, Canadian and Mexican editions share an identical code, the match is exact by construction. UK SIC 2026 is built directly on NACE Rev 2.1 — identical codes with identical titles are exact.
Verified title identity
Systems that renumber ISIC (UK SIC, NACE, NIC) are never matched by code alone — that produces wrong answers (UK SIC 01.42 is cattle; ISIC 0142 is horses). We only link classes whose titles are identical after normalizing boilerplate ("other than" ≡ "except").
Derived evidence
Broader mappings (a whole section or division) are derived from the class-level evidence beneath them, weighted by how many verified class pairs support each candidate — and labeled exact only when the evidence is ≥90% mutually exclusive in both directions (e.g. NAICS 31-33 ↔ ISIC C).