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KSEF-BUS-124 INFERRED Error KSeF Guard Only

Invalid NIP format

Niepoprawny format NIP

Problem

NIP (tax identification number) has an invalid format or incorrect checksum. NIP should consist of 10 digits and pass the weighted checksum validation.

How to Fix

Verify the seller's or buyer's NIP — a valid NIP consists of 10 digits without dashes, with a correct checksum (weights: 6-5-7-2-3-4-5-6-7).

Source Reference

Brochure FA(3), Section Field Formats, point 10

Page 6

View source PDF

Source Quote

“NIP number should consist of 10 digits without separators.”
Description SHA-256: 079fc4a1ba26…

Justification

FORMAT

Legal Basis Chain

1

NIP is mandatory in the Podmiot1 element

Obligatoryjność NIP w elemencie Podmiot1

“The Podmiot1 element is a mandatory component of the structured invoice. Its key field is the Tax Identification Number, which is essential for taxpayer authorisation within the KSeF. If the Tax Identification Number is not provided in the corresponding field, issuing the invoice within the KSeF will not be possible.”
Brochure FA(3), Section Podmiot1 (Page 10)
2

NIP format: digit sequence without separators

Format NIP: ciąg cyfr bez znaków rozdzielających

“10. Tax identification numbers included in the structured invoice must be entered as a continuous string of digits or letters, without spaces or other separating characters. The alphabetic country code must be entered in a separate field designated for this purpose.”
Brochure FA(3), Section Formaty pól, item 10 (Page 6)
3

Buyer NIP only in the NIP field

NIP nabywcy wyłącznie w polu NIP

“NOTE The Polish taxpayer identification number (NIP) of the purchaser must be entered in the NIP field within the Podmiot2/DaneIdentyfikacyjne element. It must not be provided in the NrVatUE or NrID fields.”
Brochure FA(3), Section Formaty pól, item 10 (Page 6)