Micro-entrepreneurs with monthly sales up to PLN 10,000 (roughly €2,350) must join KSeF from 1 January 2027, and from the same date the tax authority can impose penalties on any taxpayer for invoices issued outside KSeF or with errors.
The smallest Polish sole traders and micro companies; all Polish businesses regarding penalties.
Sizes: micro · Sectors: All sectors · Applies if: We invoice other businesses (B2B)
Micro-firms: choose a free or low-cost KSeF-compatible invoicing app (the Ministry's own e-mikrofirma tool works) and obtain authentication before January 2027. Everyone else: audit your 2026 KSeF invoices for errors before penalties apply.
Fines for issuing invoices outside KSeF from 2027
Last verified 7 September 2026. Informational only, not legal advice.
Large taxpayers (2024 sales above PLN 200M) started 2026-02-01; penalties for KSeF errors suspended until 2027-01-01
Every VAT-registered business in Poland, including foreign companies with a Polish fixed establishment.