Penalties in KSeF – when and how high?

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The National e-Invoicing System (KSeF) is set to become mandatory from February 2026, bringing significant changes for entrepreneurs and accountants alike. While the main goal of KSeF is to simplify invoicing and tax control, the question of penalties has already raised concerns. Importantly, financial sanctions will not apply immediately but only from 2027.

When can penalties be imposed?

Penalties apply when a taxpayer:

• fails to issue a structured invoice via KSeF despite the obligation,

• issues a non-compliant invoice during a system outage or when KSeF is unavailable,

• fails to submit an offline invoice to KSeF within the required timeframe.

  
  

How high can penalties be?

• Up to 100% of the VAT amount shown on an invoice issued outside KSeF.

• If no VAT is shown, up to 18.7% of the total invoice value.

Taxpayers will have only 14 days to pay once the decision is delivered.

Financial, not criminal liability

The law makes it clear: breaches of KSeF rules will result only in financial penalties – not criminal tax liability.

Proportionality of penalties

Authorities will consider the severity of the breach, its frequency, any corrective actions, and the taxpayer’s personal and financial situation. In exceptional cases, penalties may be waived.

From when?

Although KSeF becomes mandatory in 2026, penalties will only be enforced from 2027.

Legal basis: Article 106ni of the Act of 11 March 2004 on Value Added Tax (Journal of Laws of 2025, item 775, as amended)