Wrong VAT ID (NIP) on an e-Invoice issued in KSeF — what does the Ministry of Finance say?

Paweł Gorzelec
7 days ago
2 min read

With the mandatory rollout of Poland’s National e-Invoicing System (KSeF) approaching, businesses and accountants are raising practical questions — especially about mistakes in the buyer’s VAT ID (NIP). Today, many “minor” errors can be fixed with a correction note, but that path is ending soon.

The current state

Under the VAT Act, minor mistakes (including certain buyer details like NIP) can be corrected by the buyer via a correction note. However, any error affecting tax base or VAT amounts must be fixed with a corrective invoice.

What changes with KSeF?

As of 1 February 2026, Article 106k of the VAT Act (allowing buyer-issued correction notes) will be repealed. In practice:

any mistake “in any item of the invoice” is corrected by the seller via a corrective invoice (Art. 106j(1) and (2)(6)),
where amounts/tax base are not affected, the corrective invoice must state the correct content of the corrected items.

Ministry of Finance guidance

The MoF explains KSeF standardizes and semantically validates data, reducing errors. If an error does occur:

an invoice with a wrong NIP should be corrected “to zero”,
and then re-issued with the correct NIP.Other mistakes are also handled via corrective invoices under Art. 106j.

Practical workflow (step-by-step)

Detect wrong buyer NIP on an invoice in KSeF.
Issue a “zeroing” corrective invoice for the erroneous document.
Re-issue the invoice with the correct NIP (same content otherwise).
Inform the buyer and align settlements if payment has already occurred.

Implications for taxpayers

More documents to process when NIP is wrong (zeroing correction + re-issue).
Seller-driven error handling — buyers won’t fix formalities via notes.
Need for procedures (robust NIP validation before issuing).

Good practices before 1 Feb 2026

ERP validations (format/existence checks for NIP before sending to KSeF).
NIP checklist for billing teams (KRS/CEIDG/“white list” checks for new customers).
Templates for informing about a zeroing correction and re-issue.
Internal SOP: who/when/how issues corrections in KSeF.
Team training: difference between notes (until 31 Jan 2026) and corrections (from 1 Feb 2026).