Reverse Italian tax code decoder

What is a reverse codice fiscale lookup?

Every person registered in Italy has a codice fiscale, a 16-character tax code built from their personal details. You need it to sign a rental contract, open a bank account, start a job, see a doctor or buy a SIM card. Because the code is generated with fixed rules, it can also be read backwards. That is what this tool does: paste a code and it tells you the holder’s sex, date and place of birth, age, and whether the code is formally valid.

It is particularly useful if you are dealing with Italian paperwork from abroad, if you are an employer or landlord checking the details of a new employee or tenant, or if you simply want to understand what those sixteen characters on your health card actually mean.

How the Italian tax code is built

Take the textbook example RSSMRA80A01H501U, which belongs to a fictional Mario Rossi, born in Rome on 1 January 1980.

• Characters 1–3 (RSS): the first three consonants of the surname, then vowels, then X if the surname is very short.
• Characters 4–6 (MRA): the first name. If it has four or more consonants, the 1st, 3rd and 4th are used.
• Characters 7–8 (80): the last two digits of the year of birth.
• Character 9 (A): the month, as a letter: A Jan, B Feb, C Mar, D Apr, E May, H Jun, L Jul, M Aug, P Sep, R Oct, S Nov, T Dec.
• Characters 10–11 (01): the day of birth. For women, 40 is added, so a woman born on the 1st has 41.
• Characters 12–15 (H501): the cadastral (Belfiore) code of the Italian municipality of birth, or a code starting with Z for people born abroad.
• Character 16 (U): a check character calculated from the other fifteen, used to catch typos.

Born outside Italy?

If you were born abroad, characters 12–15 contain the code of your country instead of an Italian town. It always starts with Z: Z404 is the United States, Z114 the United Kingdom, Z110 France, Z131 Spain. Our decoder recognises every country code, including some historical ones, and shows the country name.

Letters instead of numbers: omocodia

When two people would end up with exactly the same code, the Italian Revenue Agency changes one or more digits of the second code into letters (0 becomes L, 1 becomes M, and so on up to 9, which becomes V). This is called omocodia. A code such as RSSMRA80A01H50MM is perfectly valid, and the tool decodes it correctly and shows you the original base code.

Common mistakes the tool catches

Most invalid codes are simple typos: the letter O instead of zero, I instead of 1, S instead of 5, or a missing character. When the check character does not match, the decoder highlights the wrong block in red and suggests the most likely corrections, so you can fix the code before submitting a form.

Privacy and limits

The tool runs entirely in your browser: no code is sent to or stored on our servers. It performs a formal check only. It cannot tell you whether a code has actually been issued or to whom; for that you need the Agenzia delle Entrate. CodiceFiscaleInverso is an independent service and is not affiliated with any Italian public authority.