OIB
Croatia's Osobni identifikacijski broj, an 11-digit identifier used for both individuals and legal entities, with the same number serving as the Croatian VAT number when prefixed with HR.
What it is
The OIB (Osobni identifikacijski broj, or Personal Identification Number) is Croatia's universal identifier for natural persons and legal entities. It is an 11-digit number issued by the Tax Administration (Porezna uprava) and was introduced in 2009 to replace a fragmented set of earlier identifiers. Every Croatian taxpayer, individual or company, holds exactly one OIB for life.
Where you meet it
For EU VAT purposes, the Croatian VAT number is the OIB prefixed with HR, giving a 13-character string: HR followed by the 11-digit OIB (e.g. HR12345678901). This is the number queried through VIES when validating a Croatian counterparty. The same OIB also appears on Croatian income tax filings, social security records, and public company registry entries, because a single number serves all these purposes.
Checksum
The last digit of every OIB is a check digit computed using a MOD-11 algorithm. A number where the computed check digit would be 10 is not issued. This means a single transposition in any of the first 10 digits can be detected before a registry call is made.
Common confusions
- The OIB is used for both individuals and legal entities, which is unusual compared to most EU countries that maintain separate identifier series. A company OIB and a director's personal OIB are structurally identical.
- The HR prefix is required for EU VAT validation. The 11-digit OIB alone, without the prefix, will not resolve in VIES.