Home ALV-numero Finland
Finland ALV-numero validator
How the ALV-numero format works
- Format
- FI + 8 digits
- Example
- FI20774740
Things to watch for
- The domestic Y-tunnus business ID uses a hyphen; the VAT number does not
- A weighted mod-11 checksum over all 8 digits must divide evenly
^FI[0-9]{8}$Finland’s VAT number, the ALV-numero, is built directly from a business’s existing Y-tunnus (business ID) issued by Verohallinto (the Finnish Tax Administration) — but the two aren’t written identically. The domestic Y-tunnus includes a hyphen before its final check digit, like 1234567-8; the EU-facing VAT number removes that hyphen and prepends “FI”, giving FI12345678. Same 8 digits, two different presentations depending on which form you’re filling out.
That formatting switch is a common source of rejected entries: someone pastes the Y-tunnus straight from a Finnish invoice or business registry printout, hyphen included, into a field expecting the FI-prefixed VAT format, and the number fails a check it would otherwise pass cleanly.
What the tool checks
This validator confirms the “FI” prefix, counts exactly 8 digits with no hyphen, and then runs Verohallinto’s own check-digit formula — weights 7,9,10,5,8,4,2,1 applied to the 8 digits, which must sum to a multiple of 11 — entirely in your browser, with no signup and nothing sent to a server.
What’s still unverified
A pass confirms the number is correctly formatted and checksum-valid for VAT use, not that it’s an active registration. Confirm current status through the EU’s VIES lookup or Verohallinto before treating a match as proof of registration.
Scope: ALV-numero format and check-digit validation only — not VAT registration status or filing rules.
Content last reviewed 2026-07-07.
ALV-numero FAQ
Is a Finnish VAT number the same as a Y-tunnus?
Same digits, different dress: Finland's domestic Y-tunnus business ID is written with a hyphen (e.g. 1234567-8), while the EU VAT number, the ALV-numero, strips the hyphen and adds 'FI' in front — FI12345678.
Why does copying a Finnish VAT number sometimes fail my forms?
Usually because someone copied the Y-tunnus with its hyphen still in place, or forgot to add the 'FI' prefix. The VAT number needs the hyphen removed and 'FI' added, even though the underlying 8 digits are identical.
Does this tool check the Finnish check digit?
Yes. Beyond the 'FI' prefix and 8-digit count, it runs Verohallinto's official weighted check-digit formula against the 8 digits, so a pass confirms a mathematically valid checksum, not just the right shape.