Invoice outside KSeF
If you issue an invoice outside KSeF despite the obligation, the head of the tax office imposes, by decision, a financial penalty of up to 100% of the VAT amount shown on that invoice.
up to 100% VATKSeF sanctions from 2027
until sanctions start
74
74 days · January 1, 2027
On September 16, 2026 the Ministry of Finance announced it will move the penalties to January 1, 2028. The bill is still in progress — until it is passed, the date in force is January 1, 2027. Ministry announcement
What could invoices outside KSeF
cost you?
From January 1, 2027, every invoice issued outside KSeF carries the risk of a financial penalty of up to 100% of its VAT amount (art. 106ni ustawy o VAT). Check your maximum exposure — before the tax office does.
art. 106ni ustawy o VAT
How much can an invoice outside KSeF cost?
zł
0 zł1,000,000 zł
Total monthly sales value including VAT (gross).
Share of invoices outside KSeF20%
0%100%
Estimated share of sales invoiced outside KSeF.
VAT rate
E.g. VAT-exempt sales — the penalty is based on the total amount due, up to 18.7%.
Maximum penalty
per monthup to 1,870 zł
per yearup to 22,439 zł
10,000 zł invoiced outside KSeF · incl. 1,870 zł VAT · penalty cap: 100% of VAT
Legal basis: art. 106ni ustawy o VAT. The law sets an upper limit (“up to”) — the actual amount is calibrated in the proceedings.
This calculator is for illustrative and educational purposes only. The result shows the statutory upper limit of the penalty (“up to”), not a prediction of its actual amount — penalties are imposed by the head of the tax office by way of a decision, taking into account the circumstances of each case. The information on this page does not constitute tax or legal advice.
KSeF timeline
February 1, 2026
Largest taxpayers
KSeF becomes mandatory for the largest taxpayers — 2024 sales (incl. VAT) above 200 million zł.
In forceApril 1, 2026
All other VAT payers
KSeF becomes mandatory for all other active VAT payers.
In forceJanuary 1, 2027
Micro businesses and sanctions start
End of the transition period: financial penalties up to 100% of VAT and the full obligation for everyone — it also covers cash-register invoices and micro sellers (up to 10,000 zł per month).
Sanctions startart. 106ni ustawy o VAT
What can you be fined for?
Late upload from offline mode
If you issue an invoice in offline24 or emergency mode but fail to send it to KSeF within the statutory deadline — the same penalty applies, up to 100% of the VAT amount.
up to 100% VATInvoice without VAT shown
For invoices without a VAT amount (e.g. exempt sales), the penalty may reach up to 18.7% of the total amount due shown on the invoice.
up to 18.7%Don’t wait for your first penalty
Biurko issues invoices straight to KSeF and keeps the UPO with them, and the VAT registers and the JPK_V7 are built from those same documents. Start for free.
FAQ
Frequently asked questions
Financial penalties apply from January 1, 2027. The KSeF obligation itself starts earlier — February 1, 2026 (largest taxpayers) and April 1, 2026 (everyone else) — but during the transition period no penalties are imposed (the so-called soft landing).
That is what the Ministry of Finance has announced: on September 16, 2026 it said penalties for errors in using KSeF will apply only from January 1, 2028. The change needs an amendment to the act — the bill is in progress, and until it is passed the date in force is January 1, 2027. The postponement covers the penalties, not the obligation: from January 1, 2027 KSeF also covers the smallest sellers and invoices from cash registers, and during the penalty-free period the tax office is to remind taxpayers of the obligation and check that their returns are accurate.
Under art. 106ni ustawy o VAT the penalty may be up to 100% of the VAT amount shown on the invoice, and for invoices without VAT — up to 18.7% of the total amount due. This covers invoices issued outside KSeF, invoices non-compliant with the official template in fallback modes, and offline invoices submitted late. These are upper limits — the actual amount is decided by the head of the tax office.
The penalty is not calculated automatically — it is imposed by the head of the tax office through an administrative decision, and the law only sets an upper limit (“up to”). The amount is calibrated: the office weighs the gravity and circumstances of the breach, and may waive the penalty in force-majeure cases. It is payable within 14 days of delivery of the decision.
Offline24 mode is fully legal — you issue the invoice outside KSeF and upload it later, within the statutory deadline (as a rule, no later than the next business day). A penalty only applies if you miss that deadline.
The simplest way is to issue invoices in KSeF from day one of the obligation, without waiting for January 1, 2027. Invoicing software integrated with KSeF (like Biurko) issues invoices and sends them to KSeF, keeps the UPO alongside them, and during an outage switches to offline24: the QR code and the deadline land on the invoice, and the document goes out once the system is back.