CNAE Section Validator

CNAE hierarchy: from the 21 sections down to the subclass

Beyond checking the mask, a CNAE code tells you which sector a business belongs to. This tool reads the first two digits (the divisão) and maps them to one of the 21 top-level sections (A–U) of the Brazilian activity classification — so 6201-5/01 resolves to Section J — Information and communication. It's a quick way to sanity-check that a code lands in the sector you expect.

The CNAE is a strict hierarchy with five nested levels; each level adds digits to the one above, so the same number encodes the whole chain from broad sector to fine activity.

The five levels

• Seção (letter A–U): 21 broad sectors — Agriculture (A), Manufacturing (C), Construction (F), Commerce (G), Finance (K), Health (Q)…
• Divisão (2 digits): the 62 in 6201-5/01 — this is what selects the section.
• Grupo (3 digits) and Classe (4 digits + check digit): progressively narrower.
• Subclasse (7 digits, with /NN): the Brazilian leaf level used on the CNPJ.

Why the section matters

• Sector analytics: aggregating companies by section (manufacturing vs services) for statistics and dashboards.
• Risk & licensing: whole sections carry typical regulatory burdens (e.g. Section Q health, Section F construction).
• Tax treatment: ISS vs ICMS often splits along the services/goods sections.
• Mock data / testing: confirming a generated CNAE falls in a plausible section.

Common pitfalls

• Section comes from the division, not the first letter: there is no letter in the numeric code — you derive the section from the 2-digit divisão.
• Gaps are intentional: divisions aren't fully contiguous (e.g. 34, 40 are unused), so a missing division means "no section".
• Section ≠ Simples eligibility: eligibility is by subclass, not by whole section.
• Don't infer too much: the section is a coarse bucket; tax and licensing live at the subclass.

FAQ

How many sections are there? 21, labelled A through U, each covering a range of divisions.

Where does the section letter come from? From the divisão (first two digits); the numeric CNAE never prints the letter itself.

Is the section enough for tax decisions? No — use the full subclass; the section is only a high-level grouping.