KSeF Mandatory Dates 2026: Who Must Comply and When
Exact KSeF mandatory dates for Polish businesses: February 1, 2026 for large taxpayers and April 1, 2026 for all others. Who is in scope, who is exempt, and what happens if you miss the deadline.
KSeF Mandatory Dates 2026: Who Must Comply and When
Poland's KSeF mandate rolled out in two phases in early 2026. If you missed the headlines, here is the quick reference you need.
The Two Key Dates
| Date | Who Is Affected | What Becomes Mandatory |
|---|---|---|
| 1 February 2026 | Large taxpayers (annual VAT taxable turnover >PLN 200 million in the previous tax year) | All domestic B2B VAT invoices must be issued through KSeF |
| 1 April 2026 | All remaining VAT-registered businesses in Poland | All domestic B2B VAT invoices must be issued through KSeF |
There is no further phase — after April 1, 2026, the mandate is universal for VAT payers.
How to Know if You Were a "Large Taxpayer" for February 1
The threshold is based on total VAT taxable supply turnover in the previous tax year. Specifically:
- If your VAT-taxable turnover (suma obrotów dla celów VAT) for the 2024 tax year exceeded PLN 200,000,000 (200 million złoty), you were a large taxpayer and the February 1 date applied to you.
- This figure comes from your JPK_VAT filings — it is the aggregate of all domestic and export taxable supplies.
If you were close to this threshold and unsure, your tax advisor should have confirmed your status before February 2026.
Who Is Fully In Scope
Once either threshold date applies to you, the following invoice types must go through KSeF:
- All invoices for domestic B2B sales subject to Polish VAT (23%, 8%, 5%, or 0% rate)
- Invoices for services provided in Poland to VAT-registered Polish buyers
- Invoices issued by foreign businesses registered for Polish VAT (with a Polish NIP) for domestic transactions
- Self-billing invoices (samofakturowanie) — the buyer issues the invoice on the seller's behalf, but must still submit it through KSeF on the seller's account
- Corrective invoices (faktury korygujące) — KSeF handles corrections through a structured reference to the original KSeF reference number
- Advance invoices (faktury zaliczkowe) — treated as regular KSeF invoices
Who Is Exempt
Not all transactions require KSeF. The following remain outside the KSeF mandate:
B2C transactions Invoices to consumers (non-VAT-registered private individuals) are not issued through KSeF. The standard consumer receipt or invoice process applies.
Cross-border transactions
- Export invoices (towar lub usługa z zerową stawką VAT eksport) to buyers outside Poland
- Intra-Community supplies (WDT) to EU buyers with a valid EU VAT number
- Services subject to the reverse charge mechanism where Polish VAT does not apply
Entities not registered for Polish VAT If you are below the PLN 200,000 voluntary registration threshold and have not registered for VAT, KSeF does not apply to you.
Simplified invoices and receipts Paragony fiskalne (fiscal receipts) with a NIP for amounts under PLN 450 have a separate regime and are not submitted through KSeF.
Invoices covered by margin scheme taxation (VAT marża) These have a special treatment and may be exempt or partially exempt from KSeF — confirm with your tax advisor.
What Happens If You Did Not Comply by the Deadline?
The Polish Ministry of Finance has set penalties under the KSeF Act:
For the seller:
- Fines of up to 100% of the VAT amount shown on the invoice for issuing an invoice outside KSeF when you were obligated to use it
- The invoice issued outside KSeF is considered invalid for VAT purposes — it cannot be corrected retroactively by simply re-entering it into KSeF
For the buyer:
- A buyer who accepts and deducts VAT based on a non-KSeF invoice (when the seller was obligated to use KSeF) risks having that VAT deduction disallowed during an audit
- Buyers should verify that sellers who are mandated are submitting through KSeF before booking purchase invoices
Practical reality in early 2026: The Ministry signalled that initial enforcement in the February–April 2026 period would focus on systemic/deliberate non-compliance rather than isolated technical errors. However, this grace period should not be relied upon. Businesses that have made no effort to comply face the full penalty regime.
What to Do If You Are Not Yet Compliant
If you are a business that should have been using KSeF from April 1 and you have not started:
- Do not panic — but do act immediately.
- Contact your accounting software provider and confirm KSeF module availability
- Register on the KSeF test environment (środowisko testowe) to practice before live submissions
- Conduct a review of invoices issued since your mandatory date and consult your tax advisor on how to handle the gap
- Do not continue issuing PDF invoices — switch to KSeF immediately
The KSeF portal is available at: https://www.podatki.gov.pl/ksef/
Free government KSeF access (for manual low-volume submission) is available at: https://ksef.mf.gov.pl/
Dates and thresholds confirmed by the amended KSeF Act (Ustawa o KSeF, Dz.U. 2021 poz. 1598, as amended 2025). Consult the Ministry of Finance website for the latest regulatory guidance.