Paid ZUS or tax late? Interest, czynny żal, and how to put it right

If you paid ZUS (the social insurance office) or tax late, pay the missing amount now and add late-payment interest (odsetki za zwłokę). Nobody sends you a bill first: you work the interest out yourself, and small amounts are not charged at all. A late or wrong return is a separate matter, and that is where a czynny żal (voluntary disclosure to the tax office) comes in.

How the interest is worked out

Interest runs from the day after the deadline to the day you pay (Tax Ordinance art. 53 § 4). The same rate applies to income tax, VAT and ZUS contributions (the social insurance act, art. 23, borrows the tax rules).

The rate is set by law as 200% of the lombard rate of the NBP (Poland’s central bank) plus 2%, and never less than 8% (art. 56 § 1). The lombard rate has been 4.25% since 5 March 2026, so in 2026 the rates are:

These are our sums from the legal formula, and they change whenever the NBP changes the lombard rate (art. 56c).

The formula is in a Ministry of Finance regulation: amount × days late × yearly rate ÷ 365. Tax interest is then rounded to full złoty: below 50 grosze down, 50 grosze and more up (art. 63 § 1).

Example: 3,000 PLN of VAT paid 20 days late in 2026: 3,000 × 20 × 10.5% ÷ 365 = 17.26 PLN, rounded to 17 PLN. You pay 3,017 PLN.

The Ministry of Finance’s free online calculator does the sum, even across a rate change.

When small amounts are not charged

Both systems skip interest below a threshold:

So 2,000 PLN of ZUS paid 30 days late carries about 17.26 PLN of interest: under 48.06 PLN, so not charged. Paid 90 days late, it comes to about 51.78 PLN, and you owe it all.

The tax figure follows the postal price list, so check the calculator first.

Watch out: a payment that covers the tax but not the interest is split between the two in proportion (Tax Ordinance art. 55 § 2; ZUS does the same under its own rules on settling contributions). A little of the tax then stays unpaid and keeps collecting interest. Pay the interest in the same transfer.

Correcting a return: the reduced rate

If the late payment happened because your return was wrong (you declared too little VAT or income tax), you correct the return (korekta deklaracji) and pay the difference. You get the reduced rate of 5.25% when both of these are true (art. 56a):

1. you file the correction within 6 months of the deadline for the original return, and
2. you pay the missing tax within 7 days of filing the correction.

It does not apply once the tax office has announced an audit, or when the correction follows its checks. It also does not apply to ZUS: the social insurance act excludes it.

What is a czynny żal, and when do you file one?

A czynny żal is a written notice to the head of your tax office (naczelnik urzędu skarbowego) saying you broke a tax rule. The Fiscal Penal Code says you are not punished for a tax offence if you report it, describe what happened, and pay the tax due within the time you are given (art. 16).

It only works if you are first. It is ineffective once the office already has documented knowledge of the offence, or has started a check or an audit aimed at it (art. 16 § 5).

When people usually file one:

• A return filed late or not at all, such as a JPK_V7M, a VAT-9M (VAT on services a VAT-exempt business buys abroad) or an annual PIT (income tax) return. Not filing a return on time is a fiscal petty offence (wykroczenie skarbowe, Fiscal Penal Code art. 56 § 4).
• Months you never declared, for example VAT on foreign services you did not know about. Our guide to VAT-UE for Google, Adobe and AWS walks through that case.

When you may not need one:

• A wrong return you correct yourself. Filing a valid correction and paying the difference promptly already protects you from a penalty for that return (art. 16a), as long as no proceedings have started.
• A single late payment of tax you declared correctly. The code punishes, as a petty offence, a taxpayer who persistently fails to pay on time (art. 57), and a court may waive the penalty if the tax was paid in full before proceedings began. The code does not say what “persistently” means, so if you are unsure, ask the tax office’s KIS helpline or an accountant.

You can file it on paper, in person, or through e-Urząd Skarbowy, the online tax office (art. 16 § 4a). The code sets no form, only that you describe the essential facts. In practice that means who you are (name, NIP tax number), what you did wrong, for which period, the amount, and that you have paid it or will pay it with interest.

For foreigners: write the notice in Polish if you can, or have it translated. The tax office works in Polish.

ZUS paid late: interest, extra charges, and your sickness pay

A sole trader’s ZUS is due by the 20th of the following month. A sp. z o.o. (limited company) pays its staff’s contributions by the 15th, while a sole shareholder paying only for themself pays by the 20th (social insurance act art. 47). When the day falls on a Saturday, Sunday or public holiday, it moves to the next working day. The details are in ZUS explained.

If you are late:

• Interest at the basic rate, unless it is 48.06 PLN or less (2026).
• ZUS may add an extra charge of up to 100% of the unpaid contributions (art. 24 ust. 1a), and not paying contributions on time is an offence with a fine of up to 46,000 PLN (art. 98).
• Instalments: if you cannot pay, ask ZUS to spread the debt out (art. 29). Interest on contributions put into instalments stops from the day after your application arrives; a smaller prolongation fee applies instead.

Your sickness pay (zasiłek chorobowy) depends on your ZUS balance, not on whether each payment was punctual:

• Since 2022, paying late no longer ends your voluntary sickness insurance.
• ZUS refuses the benefit if, on the day you fall ill, your social contribution arrears are above 1% of the minimum wage: 48.06 PLN in 2026.
• If you pay the whole debt within 6 months, you get the benefit for the whole period. After 6 months, you get it only from the day you pay.

Tip: ZUS applies each payment to your oldest debt first. If one month was short, the next full payment fills that gap and leaves the new month short. Pay the missing amount plus interest as a separate top-up. To check where you stand, ask ZUS on 22 560 16 00.

A late VAT payment or JPK file

VAT and the JPK_V7M file (the VAT records and return in one) are due by the 25th of the following month (VAT Act art. 99).

• VAT paid late, file on time: pay the VAT to your tax micro-account (your personal account number for tax) with interest at 10.5% a year.
• File sent late: send it as soon as you can, pay any VAT with interest, and consider a czynny żal for the late return. Act before the tax office does: if it finds an unfiled return with the VAT unpaid, or an understatement above 25% of the tax due and above five times the minimum wage, the increased 15.75% rate applies (Tax Ordinance art. 56b).
• Errors in the file: if the errors stop the tax office checking your transactions, it can send a request to correct them. You have 14 days to send a corrected file or explain. If you do not, it can impose 500 PLN per error (VAT Act art. 109 ust. 3h). A sole trader who is punished under the Fiscal Penal Code for the same thing is not fined twice.

How to avoid being late

The monthly deadlines in 2026:

A date that lands on a weekend or public holiday moves to the next working day; in 2026 the 20th moved to 22 June, 21 September and 21 December. The full list, including the annual returns, is in tax deadlines for 2026.

Komplet, our free Mac app, shows your deadlines with Polish holidays taken into account, and recognises tax and ZUS transfers on your PDF bank statements, so you can see which periods were paid and when.

What to do next

1. Pay the missing amount today, to your tax micro-account or your ZUS account. Every day adds interest.
2. Work out the interest with the Ministry’s calculator and pay it in the same transfer. Skip it if it falls under the threshold.
3. If a return was wrong, file a correction and pay within 7 days to get the reduced rate.
4. If a return was late or missing, file it and consider a czynny żal before the tax office contacts you.
5. If you cannot pay ZUS, ask for instalments rather than waiting.
6. Put the 15th, 20th and 25th in your calendar, with a reminder a few days before.