RG-RJ Format Validator

Rio de Janeiro RG: same mask, no public check-digit standard

The RG issued in Rio de Janeiro is produced by the state identification body — historically the IFP (Instituto Félix Pacheco) and the Detran-RJ identification service. It uses the same visual mask as many states, NN.NNN.NNN-D (8 base digits plus a final character that may be a digit or X). Unlike São Paulo, RJ does not publish a widely documented check-digit algorithm, so the only portable, reliable validation is format/mask — which is what this tool does.

This matters in practice: a system that tries to apply São Paulo's mod-11 rule to an RJ number will reject many genuine RJ RGs. Treating the RG as a state-scoped, format-checked identifier — always paired with RJ and the issuing body — is the correct approach.

Why format-only is the right call for RJ

• No official algorithm: there is no public, authoritative mod-11 spec for RJ comparable to SP's.
• False rejections: borrowing another state's checksum produces wrong "invalid" results.
• Authoritative check: only the state's records (or the document itself) confirm a real RG; format is a sanity gate.

Where it shows up

• Onboarding & KYC: RJ-issued IDs in banking, telecom and HR forms.
• Public services: Detran-RJ and state systems reference the RG.
• Document pairing: cited as RG 12.345.678-9 IFP/RJ (or Detran/RJ).
• Mock data / testing: generating mask-valid RJ RGs for form QA and synthetic fixtures.

Gotchas

• Don't apply SP's mod-11: it's specific to São Paulo and will misjudge RJ numbers.
• The final X is valid: keep it uppercase; it is part of the identifier, not a typo.
• Always scope by state: an RJ RG is only meaningful alongside its UF and issuer.
• CIN transition: new RJ identity cards are CPF-keyed under the national CIN; the legacy RG stays valid.

FAQ

Does RJ have a check digit? The printed number ends in a verifying character, but there is no public, authoritative algorithm to recompute it the way SP documents one — so format validation is the practical standard.

Can I validate an RJ RG with the SP rule? No — that produces false negatives. The two states are independent.

Is the RG the same across Brazil? No. Each state issues its own; the CIN/CPF unification is what finally makes identity nationally consistent.