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Croatia OIB (VAT number) validator
How the OIB (VAT number) format works
- Format
- HR + 11 digits
- Example
- HR24076340234
Things to watch for
- Uses the same 11-digit OIB as the national personal/business ID
- Validated with the ISO 7064 MOD 11,10 check digit, same as the standalone OIB
^HR[0-9]{11}$Croatia doesn’t issue a separate VAT-only number. Instead, a Croatian VAT identifier is simply “HR” placed in front of the holder’s existing OIB (Osobni identifikacijski broj) — an 11-digit personal or business identification number that Croatia already uses for tax filing, company registration, healthcare, and other government services. A full VAT number looks like HR12345678901: two letters, eleven digits, no exceptions.
That reuse is the detail worth knowing. Where most EU countries mint a VAT number distinct from other tax IDs, Croatia’s VAT-Porezna uprava (tax administration) simply prefixes the same OIB every resident and business already holds. So an 11-digit VAT number and an 11-digit personal OIB aren’t a coincidence — for a sole trader, they can be the identical string of digits.
The format rule
This validator checks for the “HR” prefix followed by exactly 11 digits — the full length of an OIB — and then runs the OIB’s own official ISO 7064 MOD 11,10 check-digit algorithm, run entirely in your browser with nothing sent to a server. A pass confirms length, prefix, and a mathematically valid checksum.
Limits of this check
A checksum-valid number isn’t proof of live VAT registration. Confirm current status through the EU’s VIES lookup or Croatia’s Porezna uprava before treating a number as a verified, active registration.
Scope: format, length, and OIB checksum validation — not VAT registration status or filing rules.
Content last reviewed 2026-07-07.
OIB (VAT number) FAQ
Is a Croatian VAT number the same as an OIB?
Functionally yes — Croatia's VAT number is simply 'HR' placed in front of the person or company's existing 11-digit OIB (Osobni identifikacijski broj), the same master ID used for tax, business registration, and personal identification.
Why is a Croatian VAT number 11 digits when most neighbors use 8 or 9?
Because it's not a VAT-specific number at all — it's the OIB, a general-purpose national identifier issued to every person and legal entity in Croatia, reused here for VAT purposes rather than a separate scheme being created.
Does this tool check the OIB's own check digit?
Yes. Beyond the 'HR' prefix and 11-digit count, it runs the OIB's official ISO 7064 MOD 11,10 check-digit algorithm against the 11th digit, so a pass confirms a mathematically valid checksum.