Partita IVA validator
The partita IVA check digit, worked out.
Output
Paste or type above to see the result here.
Your files stay on your device
This tool runs entirely in your browser. What you paste is processed on your device and is never sent to a server, so it is safe to use with tokens, keys and unpublished text.
Example
Example: a partita IVA from an invoice, and two ways of mistyping it
An Italian supplier’s invoice gives its VAT number as IT01234567897 (made up, but correctly formed). Paste it, and on the next lines two mistyped copies: one with the last digit wrong, one with the first two digits swapped.
- Digits in odd places (1st, 3rd … 9th) are added as they are: 0 + 2 + 4 + 6 + 8 = 20.
- Digits in even places (2nd … 10th) are doubled, taking 9 off any result over 9: 1×2 + 3×2 + (5×2 − 9) + (7×2 − 9) + (9×2 − 9) = 23.
- 20 + 23 = 43; the check digit brings that to the next multiple of 10: 10 − 3 = 7. The IT prefix is ignored.
| Typed | Check digit worked out | Result |
|---|---|---|
| IT01234567897 | 7 | Valid |
| 01234567890 | 7 (typed: 0) | Not valid |
| 10234567897 | 8 (typed: 7) | Not valid |
| IT 0123456789 | – | Not valid: 10 digits, 11 expected |
The number on the invoice passes with check digit 7, and both typos are caught, each with the digit it should have ended in. Each line also splits the number into matricola 0123456 and ufficio 789.
How it works
- Paste one number a line; dots, dashes and spaces are fine.
- Each is checked for its length and its check digits.
- The result shows each step of the calculation, and where a number fails.
Frequently asked questions
- How is a partita IVA checked?
- Add the digits in odd places; double those in even places, subtracting 9 when the result is over 9, and add them too; the check digit makes the total a multiple of 10.
- Can I type “IT” in front?
- Yes: the IT prefix of the EU VAT number is accepted and ignored.
- Does a valid check digit mean the number exists?
- No — only that it is correctly written. Whether it was issued, and to whom, only the issuing authority can say. The checker never makes up numbers either: it checks the ones you type.
- What do the eleven digits mean?
- The first seven are the taxpayer’s own number (matricola), the next three the code of the tax office that issued it (ufficio), and the last is the check digit. The checker shows the split under each number: for 01234567897, matricola 0123456 and ufficio 789.
- Does it catch every typo?
- Every single wrong digit, yes: changing one digit always changes the check digit. Two neighbouring digits swapped are caught too (10234567897 instead of 01234567897 needs an 8, not a 7), except a swap of 0 and 9.
- Is anything uploaded?
- No. The check is worked out in your browser, and nothing you type leaves your computer.