Does an OIB contain a date of birth or gender?

No. Unlike older identifiers, the OIB is a random 11-digit number with no embedded date or gender. Only the check digit can be verified offline.

Which algorithm does the OIB use?

The eleventh digit is computed with the ISO 7064 MOD 11,10 algorithm over the first ten digits.

No. All validation happens locally in your browser and nothing leaves your device.

Croatia OIB Validator

Verify a Croatian OIB with the ISO 7064 MOD 11,10 check digit.

Croatian OIB validator

The OIB (Osobni identifikacijski broj) is Croatia’s 11-digit personal identification number. It is randomly assigned and carries no date of birth or gender — the only thing verifiable offline is its ISO 7064 MOD 11,10 check digit.

Paste a number and this tool computes the expected check digit and confirms whether it matches — all in your browser, with nothing uploaded.