BT-63 Seller Tax Registration

What is BT-63?

BT-63 (Seller tax registration identifier) holds tax registration numbers that are separate from the VAT identifier (BT-31). This is relevant in countries where businesses have both a VAT number and a separate national tax registration.

Requirements

When to Use BT-63

Country Identifier Use Case
------------------------------
Germany Steuernummer (tax number) Domestic invoicing (non-VAT-registered small businesses)
Italy Codice Fiscale When different from Partita IVA
France SIRET Establishment-level tax ID

In Germany, small businesses under the Kleinunternehmerregelung (§19 UStG) may not have a USt-IdNr (VAT number). They use their Steuernummer in BT-63 instead.

In UBL XML

  12/345/67890
  
    TAX
  

Note: BT-63 uses TaxScheme ID "TAX" (not "VAT" like BT-31).

In CII XML

  12/345/67890

Note: CII uses schemeID "FC" (Fiscal Code) for BT-63, versus "VA" for BT-31.

BT-31 vs BT-63

Field Purpose TaxScheme (UBL) schemeID (CII) -------------------------------------------------
BT-31 VAT identifier VAT VA BT-63 Tax registration TAX FC

An invoice can contain both BT-31 and BT-63.

Common Errors