Italian Codice Fiscale Validator

Codice Fiscale: Italy's 16-character tax code, derived from your name and birth

The Italian Codice Fiscale is a 16-character alphanumeric code that uniquely identifies a person for tax and administrative purposes. Unlike a random number, it is derived from your data: surname, first name, date of birth, sex and place of birth — so two people can occasionally collide (homocodia), which the authorities resolve by substituting letters. This tool validates the structure and the final check character.

The last letter is a checksum computed with a special odd/even position table mod 26 — the example RSSMRA80A01F205X (a fictitious "Mario Rossi") ends in X because that's what the algorithm produces over the first 15 characters.

How the 16 characters are built

• 3 letters from the surname (consonants first), then 3 from the first name.
• 2 digits: year of birth; 1 letter: month (A=Jan … T=Dec).
• 2 digits: day of birth — +40 for women (so day 41–71 means female).
• 4 characters: the Belfiore code of the birthplace (1 letter + 3 digits); 1 check letter.

Where it matters

• Everything official: contracts, healthcare (tessera sanitaria), banking, employment and tax filings.
• e-invoicing: required on Italian fatture and SPID digital identity.
• Derivable but verified: you can reconstruct it from personal data, but only Agenzia delle Entrate issues the official one.
• Mock data / testing: validating the structure and check letter before a registry call.

Common pitfalls

• Day +40 for women: a birth day above 31 isn't an error — it encodes sex.
• Homocodia: collisions are resolved by replacing digits with letters, so some valid CFs have letters where you'd expect numbers.
• Check letter is mod 26: it uses position-dependent odd/even tables, not a simple sum.
• Valid ≠ assigned: a structurally correct CF may not match a real registered person.

FAQ

Can I compute my own Codice Fiscale? You can derive a candidate from your data, but the official one (handling homocodia) is issued by the tax agency.

Why does a woman's code show a day like 52? Women get +40 added to the birth day, so 41–71 maps back to days 1–31.

What is the Belfiore code? A 4-character code for the comune (or foreign country) of birth, maintained by ISTAT.