Reverse Codice Fiscale — Get Date, Place of Birth and Sex
Calculator
Reverse Codice Fiscale
Enter a codice fiscale (Italian tax code) and get sex, date and place of birth, with verification of the check character and detection of omocodia (code collisions)
The calculator applies the rules of the D.M. 23 dicembre 1976 (Ministerial Decree of 23 December 1976): month letters A B C D E H L M P R S T, day increased by 40 for women, check character calculated on the first fifteen characters and the omocodia table (0→L, 1→M, 2→N, 3→P, 4→Q, 5→R, 6→S, 7→T, 8→U, 9→V). The names of municipalities and foreign countries are read from the list of cadastral codes downloaded from the site, so an active connection is required. Note: from the code you can derive only sex, date and place of birth; first name and surname cannot be reconstructed and the year has only two digits, so the century remains an assumption. A correct check character means the code is well formed, not that it has actually been assigned: the official verification is done on the free service of the Agenzia delle Entrate (Italian Revenue Agency).
Smart home: risparmio + sicurezza
Con Imou monitori consumi e sicurezza della casa da un'unica app. Ottimizza bollette e dispositivi.
More Details
Reverse codice fiscale: how decoding works
The codice fiscale (Italian tax code) of individuals is not a random string: it is built from personal data according to fixed rules, so it can be read backwards. This free calculator takes a 16-character code and derives the sex, the date of birth and the municipality or foreign country of birth, verifies the check character and flags any omocodia. The calculation takes place in your browser: only the public list of cadastral codes is downloaded from the site, to translate the last four positions into the name of the municipality.
One limitation must be stated right away, because no calculator can overcome it: from the codice fiscale you cannot trace back the first name and surname, and the year has only two digits, so the century remains an assumption.
What each position of the code says
The structure is set by the ministerial decree of 23 December 1976:
| Positions | Content | Decodable? |
|---|---|---|
| 1-3 | Three characters from the surname | No, only the letters |
| 4-6 | Three characters from the first name | No, only the letters |
| 7-8 | Last two digits of the year | Yes, but without the century |
| 9 | Month letter | Yes |
| 10-11 | Day, increased by 40 for women | Yes, day and sex |
| 12-15 | Cadastral (Belfiore) code of the place | Yes |
| 16 | Check character | Used for verification |
The month letters do not follow the alphabet: they are A January, B February, C March, D April, E May, H June, L July, M August, P September, R October, S November, T December.
Sex is read from the two digits of the day: from 01 to 31 the code belongs to a man, from 41 to 71 to a woman, because for women the day is increased by forty.
Decoding example
Let's take RSSMRA85M01H501Q: it is a synthetic code, built for this example with the official algorithm, and it does not belong to any real person. Here is how the calculator reads it:
| Part of the code | Meaning | Result |
|---|---|---|
RSS | Letters from the surname | cannot be reconstructed |
MRA | Letters from the first name | cannot be reconstructed |
85 | Year digits | 1985 (2085 would be in the future) |
M | Month letter | August |
01 | Day, below 40 | day 1, male |
H501 | Cadastral code | ROMA (RM) |
Q | Check character | correct, code well formed |
The result is man, born on 1 August 1985 in Rome. A second synthetic example, BNCGLI90T52F205A, gives woman, born on 12 December 1990 in Milan: the T is December and 52 equals 12 + 40.
The check character and omocodia
The last character carries no personal information: it is a check code. It is obtained by assigning a numeric value to the first fifteen characters — with two different tables for odd and even positions — adding them up and converting into a letter the remainder of the division by 26 (0 = A, 1 = B, … 25 = Z). If it does not match the written character, there is almost always a transcription error. Be careful, though: a correct check only means the code is well formed, not that it has actually been assigned to someone. The official verification is done on the free service of the Agenzia delle Entrate.
It can happen that two different people generate the same code: this is omocodia. In that case the Agenzia delle Entrate replaces one or more digits with letters, starting from the rightmost digit, according to the table 0→L, 1→M, 2→N, 3→P, 4→Q, 5→R, 6→S, 7→T, 8→U, 9→V, and recalculates the check character. The replaceable positions are the seven numeric ones — 7th and 8th (year), 10th and 11th (day), 13th, 14th and 15th (cadastral code) — hence the maximum of 128 variants. The calculator recognises the substitutions, converts the letters back to the original digits and shows the “clean” code: RSSMRA85M01H5LMT is the omocodic variant of RSSMRA85M01H501Q, with two digits replaced in the 14th and 15th positions and the same 1 August 1985 in Rome.
Abolished municipalities, foreign countries and century ambiguity
The last four positions contain the Belfiore code. If it starts with Z it is not an Italian municipality but a foreign country, and the calculator shows its name. Many codes belong to abolished or renamed municipalities: they remain valid for people born there earlier, so they are shown anyway, with the date of abolition and the name in use on the date of birth.
The century ambiguity remains: the digits 05 can mean 1905 or 2005, and there is nothing in the code that allows them to be told apart. The calculator shows the most recent year compatible with today's date and states the alternative when one exists. Some cases are settled by the calendar: a 29 February with year 00 can only be 2000, because 1900 was not a leap year.
Frequently asked questions
Can you trace the first name and surname from the codice fiscale?
No. The first three letters derive from the consonants of the surname and the next three from those of the first name, but the transformation is irreversible: different surnames and names produce the same letters. From the code you can derive with certainty only sex, day and month of birth and place of birth; the person's name can only be known from documents or official databases.
How can you tell whether a codice fiscale belongs to a man or a woman?
Look at the tenth and eleventh positions, i.e. the two digits of the day. If the number is from 01 to 31 the code belongs to a man; if it is from 41 to 71 it belongs to a woman, because for women the day of birth is increased by forty. To get the real day just subtract 40: the value 52 corresponds to day 12.
Why can't you be sure of the year of birth derived from the codice fiscale?
Because the codice fiscale contains only the last two digits of the year. The digits 85 can indicate 1985 or 2085, the digits 05 1905 or 2005: the century is not written anywhere. The calculator shows the most recent year compatible with today's date and flags the other possibility when it exists, without passing it off as certain.
What is omocodia and how can you recognise it in the codice fiscale?
Omocodia occurs when two different people generate the same codice fiscale. The Agenzia delle Entrate makes it unique by replacing one or more digits with letters, starting from the rightmost one, according to the table 0→L, 1→M, 2→N, 3→P, 4→Q, 5→R, 6→S, 7→T, 8→U, 9→V, and recalculating the check character. The calculator recognises letters out of place in the seven numeric positions, converts them back to the original digits and indicates which positions have been modified.
Related tools: the codice fiscale calculator (for the opposite path, from personal data to the code), the partita IVA (VAT number) check, the IBAN check and the age calculator (once the date of birth has been derived).
