How to Pay a PIT Underpayment in Poland

If your PIT return shows you owe money, pay it to your mikrorachunek (mikrorachunek podatkowy) before April 30 using a tax transfer in your banking app. The balance you owe is called a niedopłata (niedopłata), and it just means your employer or other payers didn't withhold enough tax during the year. Not a penalty, not a problem, just a bill.

What Creates a Niedopłata

A niedopłata appears when the total tax on your annual return exceeds the advance payments and withholdings made throughout the year.

If you had a single salaried job all year, your employer's monthly withholdings usually cover the full liability. But a few common situations create a gap:

• You had two or more employers during the tax year. Each one withheld tax as if their salary were your only income. Neither knew about the other, so the combined income pushing you into a higher bracket was never accounted for.
• You did freelance or contract work (umowa zlecenie, umowa o dzieło) alongside regular employment. Contracts typically use flat withholding rates that don't match your actual effective rate.
• You reported investment income, rental income, or foreign-source income in Poland.
• You lost eligibility for a tax relief you benefited from during the year.

The first scenario is by far the most common for foreigners. If you changed jobs mid-year, expect a niedopłata.

Finding Your Underpayment Amount

The fastest way is Twój e-PIT (Twój e-PIT), Poland's pre-filled online return at e-pit.podatki.gov.pl. Log in with your Profil Zaufany, mObywatel, or e-dowód. The system pulls data from your employers and shows the balance on your PIT-37 or PIT-36 summary. A positive amount due to the tax office is your niedopłata.

If you file through a Polish accountant (biuro rachunkowe) or commercial tax software, the final calculation page shows the same number.

For a manual sanity check, compare the tax withheld on your PIT-11 (sent by your employer by the end of February each year ^[1]) against the tax calculated on your return. The difference is your niedopłata or nadpłata (nadpłata, an overpayment in your favor).

Where to Send the Payment

All PIT payments go to your mikrorachunek podatkowy, a personal tax payment account assigned to every taxpayer in Poland ^[2]. It is a 26-digit IBAN-format number tied to your PESEL (for individuals) or NIP (for businesses). The number is permanent. It never changes regardless of where you live or which tax office handles your case ^[3].

Generate yours at the official tool: podatki.gov.pl/mikrorachunek-podatkowy. Enter your PESEL or NIP and the system returns your account number instantly ^[2]. If you generated it in a previous year, the number is the same.

To verify a mikrorachunek before transferring money, paste it into the Mikrorachunek Checker. The tool extracts the PESEL or NIP embedded in the account number so you can confirm it belongs to you.

Do not use old tax office account numbers. Before 2020, payments went to individual tax office bank accounts. PIT, CIT, and VAT payments now go exclusively through the mikrorachunek system ^[4]. Any old account numbers in your records or on outdated websites are wrong for PIT.

How to Fill In the Bank Transfer

Polish tax payments use a special format called a tax transfer (przelew podatkowy). Most banking apps have this as a separate option from a standard domestic transfer. Look for "przelew podatkowy" or "przelew do US" in your bank's transfer menu.

Recipient name: Urząd Skarbowy. Some banks pre-fill this.

Account number: Your 26-digit mikrorachunek. Double-check every digit.

Amount: The exact niedopłata from your return. Pay in full. Partial payments are technically possible but trigger interest on the remaining balance, so there's no upside.

Taxpayer identification: Your PESEL (individual) or NIP (business). The tax transfer form has a dedicated field for this.

Tax form symbol (symbol formularza): This tells the tax office which tax you're paying ^[5]. Use the one matching your return:

• PIT-37 for employment income only
• PIT-36 for self-employment, multiple sources, or foreign income
• PIT-36L for flat 19% business tax
• PIT-28 for ryczałt/lump-sum tax (including rental income)
• PIT-38 for capital gains
• PIT-39 for real estate sale

Tax period: The year the tax applies to, not the year you're filing. Filing your 2025 return in 2026? Enter 2025.

Transfer title (tytuł): Some banks auto-generate this from the other fields. If you need to enter it manually, use the form symbol followed by the tax year. Example: PIT-37 za 2025.

Payment Deadline

The deadline to pay is the same as the deadline to file: April 30 of the following year, for all main PIT forms ^{[5] [7]}. If April 30 falls on a weekend or public holiday, the deadline moves to the next business day.

Before 2023, PIT-28 had an earlier February deadline. The Polski Ład reform moved it to April 30 along with everything else.

The payment counts as made on the date the money leaves your bank account, not when it arrives at the tax office. A transfer initiated on April 30 before midnight is on time.

You can also pay before filing. If you already know the amount from Twój e-PIT, there's no reason to wait. Many people transfer early to avoid the April 30 crunch.

What Happens If You Pay Late

Two things.

Interest (odsetki za zwłokę). The tax office charges daily interest on overdue tax from the day after the deadline until the day you pay. The rate is set by formula: 200% of the NBP lombard rate plus 2%, with a minimum of 8% ^[6]. It changes whenever the NBP adjusts its rates. It was 14.5% through most of 2023-2024 and has since dropped through a series of rate cuts. Always verify the current rate when you pay. The Ministry of Finance publishes updates in Monitor Polski.

You calculate the interest yourself using the formula: (overdue amount × interest rate × days overdue) / 365. Add the interest to the original amount and send the combined total to your mikrorachunek in one transfer. If the calculated interest comes to 8.70 PLN or less, you don't owe it. The tax office waives amounts below that threshold ^[6].

Online interest calculators (kalkulatory odsetek podatkowych) can compute the exact amount for you.

Potential fine for non-filing. If you also didn't file the return, that's a separate and more serious problem. Interest applies to late payment. Fines apply to late filing. They are independent obligations.

Paying from a Foreign Bank Account

If you don't have a Polish bank account, you can pay by international wire transfer. You need:

• Your mikrorachunek in full IBAN format: PL + 26 digits
• The SWIFT/BIC code for the National Bank of Poland: NBPLPLPW ^[2]
• The same transfer details described above (PESEL/NIP, form symbol, tax period)

International transfers take 1-3 business days depending on your bank and intermediaries. If you're paying close to April 30, start early.

Opening a Polish bank account specifically for tax payments is worth considering if you plan to stay. Most digital banks operating in Poland let you open an account online, and domestic transfers arrive the same day.

If You Have an Overpayment Instead

If your return shows a negative balance, that's a nadpłata and the tax office owes you. Overpayments from PIT-37 and PIT-36 filed through Twój e-PIT are typically refunded within 45 days to the bank account in your return ^[5]. Paper returns take up to 3 months ^[5]. You don't need to do anything. Just make sure the bank account in your return is correct and active.

Common Questions

Can I split the payment into installments?

Not automatically. If you can't pay the full amount by April 30, you can apply to your tax office for a decision to defer or split the payment (rozłożenie na raty). This requires a formal request and is granted at the office's discretion. Interest still accrues until you get a decision.

What if I accidentally overpay?

The tax office will either apply the excess to future tax obligations or refund it. You can submit a request (wniosek o stwierdzenie nadpłaty) specifying that you want the money back to your bank account.

Does paying the niedopłata count as filing my return?

No. Payment and filing are separate. You must still submit your PIT return by April 30 even if you've already paid. If you use Twój e-PIT and don't take any action, the system auto-accepts your pre-filled return on April 30, but relying on this is risky if the pre-filled data is wrong.

I just arrived in Poland mid-year. Will I definitely have a niedopłata?

Not necessarily. If you had only one employer for the remainder of the year, withholdings may cover your liability. But if you earned income in another country that's taxable in Poland under a double taxation treaty, you might owe extra. Check your return.

References

1. Individual Tax Administration in Poland — PwC Worldwide Tax Summaries — taxsummaries.pwc.com
2. Mikrorachunek Podatkowy (Tax Micro-Account) — podatki.gov.pl
3. Mikrorachunek Podatkowy for PIT, CIT, and VAT — biznes.gov.pl
4. Mikrorachunek Podatkowy Effective 1 January 2020 — Ministry of Finance — gov.pl
5. PIT Basic Information — Filing Deadlines, Payment, and Refund Rules — podatki.gov.pl
6. Ordynacja Podatkowa (Tax Ordinance Act) — Art. 54 and Art. 56 — isap.sejm.gov.pl
7. PIT Significant Developments — PIT-28 Deadline Extension to April 30 — PwC — taxsummaries.pwc.com