Glossary Term

NIP

NIP is the Polish tax identification number (Numer Identyfikacji Podatkowej), a 10-digit code required for all B2B e-invoicing through KSeF.

Quick Facts

format
10 digits
country
Poland
registry
Ministerstwo Finansów
ksef mandatory
February 2026

Definition

What is NIP?

NIP (Numer Identyfikacji Podatkowej) is Poland's tax identification number. All VAT-registered businesses in Poland have a 10-digit NIP.

Format

  • 10 digits

  • Includes checksum validation

  • Leading zeros are significant

    • KSeF Requirement

    From February 2026, all Polish B2B invoices must be submitted through KSeF. Both seller and buyer NIP are required and validated.

    In Invoices

    1234567890

    Common Issues

  • Missing digits (entered as 9 instead of 10)

  • Invalid checksum

  • NIP not active in VAT registry