Check Tax Code
Instantly check if a tax code is formally valid
16 alphanumeric characters
Validation details
A tax code is valid for Tax Code Verification when it follows the Italian Revenue Agency algorithm exactly. This means 16 alphanumeric characters, the right structure, correct month letter, allowed day or gender range, and a matching check digit.
What Is Tax Code Verification
and How Does It Work?
Tax Code Verification is basically formal validation of an Italian Fiscal Code’s structure. The code has 16 alphanumeric characters and it uses the official algorithm, so it can catch typos before you send important documents.
This check is not the same as checking personal data in the Revenue Agency records. It cannot confirm that the code was actually assigned to a real person.
How the Online Tax Code Validator Works
The online tax code validator works in your browser, so the check runs right away. You enter your code, the validator runs the official algorithm locally, then it returns VALID or INVALID.
- Enter the 16 characters tax code (example like RSSMRA85M01H501Z)
- Press verification
- Read VALID or INVALID with a specific error
After each result you can press Verify another CF to check another code.
Formal Checks Performed by the Validator
Check Tax Code means the validator follows rules in a clear order, and it stops when something does not match. It checks length, the exact letter and number pattern, the month letter set, the day or gender ranges, and then the control character.
- Length must be exactly 16 characters
- Format pattern must match the official structure
- Month code must be one valid month letter: A, B, C, D, E, H, L, M, P, R, S, T
- Day and gender range must be 01 to 31 for male, or 41 to 71 for female
- Check digit must match the official algorithm result
16‑Character Structure of the Fiscal Code
Tax Code Verification is easier when you know what each position means in the 16-character CF. Positions 1 to 3 come from the surname letters, positions 4 to 6 from the name, then come year, month letter, day and gender, and finally municipality or foreign state code.
| Position | Characters | Meaning |
|---|---|---|
| 1–3 | letters | surname letters (consonants then vowels) |
| 4–6 | letters | name letters, with special rules |
| 7–8 | digits | birth year last two digits |
| 9 | letter | birth month letter, A to T |
| 10–11 | digits | day of birth, plus 40 for females |
| 12–15 | letters and digits | municipality cadastral code or foreign state code |
| 16 | letter | control character, CIN |
Privacy & Security
Also, to Check Tax Code the verification runs locally in the browser. Because no data leaves or stores on servers. Therefore, it complies with GDPR style expectations and delivers free instant results. All processing occurs client side.
Common Reasons a Tax Code Is Marked Invalid
Check Tax Code will show INVALID when the code does not fit one of the formal rules. The most common issues are wrong length, misplaced letters and numbers, an invalid month letter, day out of range, or a check digit that does not match.
- ✅ Example of correct format: 16 characters like RSSMRA85M01H501Z
- ❌ Wrong length: fewer or more than 16 characters
- ❌ Wrong month letter: month letter not in A, B, C, D, E, H, L, M, P, R, S, T
- ❌ Wrong day or gender range: day like 00, or a male day outside 01 to 31, or female day outside 41 to 71
- ❌ Mismatched check digit: the 16th character does not match the official algorithm
Generate and Decode Tax Codes
If you also need other steps, the site mentions two companion tools. You can use a Tax Code Calculator to generate a code from personal data, and use a Reverse Tax Code Tool to extract personal details from a valid code.
Frequently Asked Questions
Tax Code Verification raises many specific questions from users. Because accurate validation matters for administrative tasks. Do you have a question or any problems? Go to our FAQ section.
No, and this is important for Tax Code Verification. A valid CF only confirms structural correctness, it does not prove the Revenue Agency assigned it to a real person. A separate check with the Revenue Agency records is needed for that.
Check Tax Code uses the official calculation on the first 15 characters. The system assigns numeric values using odd and even rules, sums them, takes the remainder modulo 26, then converts the result into a letter for the CIN.
Yes. The validator allows free and unlimited checks, as you can press Verify another CF after each verification result and repeat the process. This is why the online tax code validator is helpful for batch-checking client lists.
What do we check?
ℹ️ Important Note
The verification checks the formal correctness of the tax code, not its association with a real identity in the Revenue Agency's records.
Need to calculate it?
Use our free calculator to generate the official code from your data.
Calculate Now →