Slovenia ID za DDV validator
How the ID za DDV format works
- Format
- SI + 8 digits
- Example
- SI12345678
Things to watch for
- This tool checks the format only; no check-digit validation is performed
^SI[0-9]{8}$A Slovenian VAT number, the ID za DDV, is “SI” followed by exactly 8 digits — SI12345678. Those 8 digits typically aren’t a separate VAT-only sequence: they’re usually the same davčna številka (tax number) FURS, Slovenia’s Financial Administration, already assigned to the business for general tax purposes, with “SI” simply added in front for EU VAT use.
That overlap means a Slovenian business’s domestic tax number and its VAT number can look like two different things at a glance — one has a country prefix, one doesn’t — while actually sharing the same 8-digit core. It’s worth checking whether a number you’ve been given already includes “SI” or is the bare domestic tax number, since only the prefixed version is formatted as a valid intra-EU VAT identifier.
What this check covers
This validator confirms the “SI” prefix and counts exactly 8 digits, entirely in your browser, with no signup and nothing sent to a server. It’s a length-and-prefix check — Slovenia’s official check-digit calculation on the 8 digits isn’t run here.
Confirming the rest
A correctly shaped ID za DDV isn’t confirmation of an active VAT registration. Confirm through the EU’s VIES lookup or FURS directly before relying on it for invoicing.
Scope: ID za DDV format only — not check-digit validation or registration status.
Content last reviewed 2026-07-07.
ID za DDV FAQ
What is ID za DDV, and how does it relate to a Slovenian company's tax number?
ID za DDV (identifikacijska številka za DDV) is Slovenia's VAT number: 'SI' plus 8 digits. Those 8 digits are typically the same as the business's davčna številka (tax number) already assigned by the Financial Administration, not a separate code issued only for VAT.
So a Slovenian business's tax number and VAT number are usually identical apart from the prefix?
Yes, in the typical case — the 8-digit davčna številka doubles as the VAT number's numeric body once 'SI' is added in front, which is why the two numbers are so often confused for being unrelated when they're really the same core identifier.
Does this tool confirm a Slovenian VAT number is currently active?
No — it checks the 'SI' prefix and 8-digit format only. Confirm live status through the EU's VIES lookup or Slovenia's FURS (Finančna uprava Republike Slovenije).