# XV-FI-13

Source: https://xmlvalid.com/rules/XV-FI-13

> The business ID (Y-tunnus) '…' has no valid check digit.

- Level: warning
- Rule sets: Finvoice 3.0 calculation and payment rules Implementation guidelines 2.6 (16 September 2025)
- Context: `/Finvoice/SellerPartyDetails | /Finvoice/BuyerPartyDetails`
- Test: `not(matches($id, '^[0-9]{7}-[0-9]$')) or fi:ytunnus($id)`

Validate a document against these rules: https://xmlvalid.com/validate