KSeF offline mode: which mode and when to send the invoice
Choose the cause, enter the issue date and the end of the failure. The calculator counts working days, skipping weekends and Polish public holidays, Christmas Eve included.
Send the invoice to KSeF by
28 December 2026
The next working day after the issue date (Art. 106nda(2)).
| Counted from | 23 December 2026 |
| Working days | 1 |
| Days off skipped | 24 December 2026 (Christmas Eve), 25 December 2026 (Christmas Day), 26 December 2026 (Second day of Christmas), 27 December 2026 |
| QR codes when handing it over outside KSeF | two: OFFLINE and CERTIFICATE |
Working days: Monday to Friday, excluding public holidays under the Public Holidays Act (Christmas Eve included since 2025).
Prepared by Radif Partners · Method · VAT Act, regulations and ministry notices checked on 25 October 2026
An invoice cannot always reach KSeF the moment it is issued, so the Polish VAT Act provides four special modes. You may choose offline24 under Article 106nda for any reason, for instance when the internet or your software is down; the invoice must be sent no later than the next working day after issue. During an unavailability of the system announced by the minister in the Public Information Bulletin, the deadline is the next working day after it ends (Article 106nh). During a failure announced in the Bulletin and in the software interface you have 7 working days from its end, and if another failure is announced meanwhile the period starts again (Article 106nf). Only a total failure, announced in the media, removes the duty to send: invoices may then be issued in any form (Article 106ng). A working day is Monday to Friday unless it is a public holiday; since 2025 Christmas Eve is also a day off, which moves deadlines in December.
Four modes in one table
The ministry gathered the rules in its table of invoicing modes. In short, under the VAT Act:
| Mode | When | Sending deadline | QR codes |
|---|---|---|---|
| offline24 (Art. 106nda) | for any reason | 1 working day after issue | two |
| unavailability (Art. 106nh) | announced in the Bulletin | 1 working day after it ends | two |
| failure (Art. 106nf) | announced in the Bulletin and software | 7 working days after it ends | two |
| total failure (Art. 106ng) | announced in the media | no sending | none |
If a failure is announced during offline24, Article 106nha applies and you count the deadline under the failure rules. The ministry pages on offline24 and on failure mode describe each mode in detail.
Two examples from the calendar
An invoice before Christmas. A business issues an offline24 invoice on 23 December 2026. The next working day is not 24 December, because Christmas Eve has been a day off since 2025 under the Public Holidays Act; then come two holiday days and a Sunday. The sending deadline is 28 December 2026.
A failure before Easter. The ministry announces the end of a failure on 2 April 2026. 7 working days skip the Easter weekend and Easter Monday, so the invoices must be sent by 14 April 2026.
What a late invoice can cost
Sending an offline invoice late is one of the breaches listed in Article 106ni. The penalty can reach 100 percent of the invoice VAT, but it applies from 2027 at the earliest, and a government bill moves it back another year. Estimate it for your invoice here:
Maximum penalty for this invoice
Maximum penalty for this invoice
PLN 2,300.00
| Current law (from 1 January 2027) | penalty possible |
| Bill, print no. 3245 (from 1 January 2028) | no penalty |
| Payment deadline | 14 days after the decision is served |
An offline invoice handed to the buyer outside KSeF needs two QR codes: CODE I labelled OFFLINE and CODE II labelled CERTIFICATE, explained in the QR code guide. Code II requires an offline-type KSeF certificate, covered under tokens and permissions.
How to prepare your business for a lost connection
Offline mode only works if you have prepared it in advance. Your invoicing software must be able to save an FA(3) file without sending it and add both QR codes, and the business must have downloaded an offline-type KSeF certificate. Agree who sends the backlog once the connection returns, because the deadline runs whether or not anyone remembers it. During longer failures follow the ministry’s notices: the seven working days count from the announced end of the failure.