Mexico CURP Validator
Check the format and verification digit of a Mexican CURP and read the sex and birth date it encodes. 100% local — nothing is uploaded. Built for Mexico.
Batch check — paste many, one per line
Validate a Mexican CURP
Paste an 18-character CURP to verify its check digit, decode sex and birth date, and see color-coded segments — all locally.
The CURP (Clave Única de Registro de Población) is Mexico's 18-character population registry code, administered by RENAPO. Structure: 4 name letters, 6 date-of-birth digits, sex (H/M), a 2-letter state code (or NE for born abroad), 3 internal consonants, a homonymy differentiator (digit for people born before 2000, letter A–Z from 2000), and a final check digit computed from a character-value table with descending weights modulo 10. This validator checks every layer locally: length, letter/digit pattern, real calendar date, known state code, and the check digit.
As with all format validators, a pass means "internally consistent", not "registered". The authoritative CURP lookup is the government service at gob.mx/curp. Last verified: July 2026.
FAQ
How is the CURP check digit computed?
Each of the first 17 characters maps to a value ("0"–"9" → 0–9, "A"–"Z" → 10–36 skipping Ñ handling), multiplied by weights 18 down to 2 and summed. The check digit is (10 − (sum mod 10)) mod 10.
What changed for people born after 1999?
Position 17 (the homonymy differentiator) is a digit 0–9 for births up to 1999 and a letter A–Z from 2000 onwards — that is how the format encodes the century.
Which state codes are valid?
The 32 federal entities each have a 2-letter code (DF/CX for Mexico City, JC for Jalisco, NL for Nuevo León…), plus NE for Mexicans born abroad. Anything else fails validation.
Is my CURP sent anywhere when I validate it?
No. The entire check runs in your browser — nothing is uploaded, logged or stored. For an official copy of your CURP, use the RENAPO service on gob.mx.