Start with one question: who pays you the interest?
Interest on savings is taxed at 19% in Poland — the so-called Belka tax. What differs is who settles it, and that depends only on where the account is.
| Account | Who settles the tax | What you do |
|---|---|---|
| At a bank in Poland | The bank withholds 19% from every interest payment | Nothing. It doesn't go on any return |
| At a bank abroad | Nobody — no Polish payer is involved | You calculate it and declare it in PIT-38, Part G |
If all your savings sit in Polish banks, you can stop reading here: the interest you see on the statement is already net of tax.
If you keep money in an account abroad — a savings account at a German or Lithuanian bank, a deposit held by a foreign provider — read on.
Not sure which applies to you? Check the statement. If a Polish tax of 19% was withheld from the interest, the provider acted as a Polish payer and there's nothing left to declare. If the interest came in gross, it's up to you.
What the law says
The MF brochure for the PIT-38 return for 2025 lists, in Part G, income under art. 30a(1), points 1–5 of the PIT Act earned abroad. One of the items is:
interest or other income from money held on the taxpayer's account or in other forms of saving, storing or investing, run by an entity authorised to do so — except money related to business activity.
That's savings interest — art. 30a(1)(3). The same part of the form also covers foreign dividends, which we explain in the guide to ETFs and dividends.
Three things follow from art. 30a:
- The rate is a flat 19%. It isn't added to your salary and doesn't touch your tax brackets.
- You pay tax on the gross interest. Nothing is deductible — no account fees, no costs.
- There is no tax-free amount. Even 5 złoty of interest is taxable.
You declare it on PIT-38 even if foreign interest is the only thing on your return — you don't need to have sold any shares.
The calculation, in four steps
- List every interest payment from the statement — with its date and gross amount.
- Convert each payment into złoty at the average NBP rate from the last business day before the day it was credited.
- Add up the złoty amounts and multiply the total by 19%.
- Round the tax up to the full grosz.
That last step is easy to get wrong. Most amounts on PIT-38 are rounded to whole złoty, and dividends are too. For interest the brochure makes an exception, based on art. 63 § 1a of the Tax Ordinance: the tax on art. 30a(1)(1–3) income is rounded up to the full grosz. So 200.6647 becomes 200.67 — not 200.66, and not 201.
Interest paid daily or monthly? Each payment is a separate piece of income, converted at its own rate. With daily interest that's 365 conversions — a spreadsheet makes it painless.
A worked example, step by step
You keep euros in a savings account at a bank in Germany. In 2025 it paid interest four times, and no tax was withheld in Germany:
| Credited on | Gross interest | Rate from | NBP table | Rate | In PLN |
|---|---|---|---|---|---|
| Mon 31 March | 60.00 EUR | Fri 28 March | 061/A/NBP/2025 | 4.1819 | 250.91 |
| Mon 30 June | 62.40 EUR | Fri 27 June | 123/A/NBP/2025 | 4.2362 | 264.34 |
| Tue 30 September | 63.10 EUR | Mon 29 September | 188/A/NBP/2025 | 4.2688 | 269.36 |
| Wed 31 December | 64.20 EUR | Tue 30 December | 250/A/NBP/2025 | 4.2293 | 271.52 |
| Total | 249.70 EUR | 1,056.13 |
These are the real NBP rates for those days — you can check them in our currency converter.
Tax:
1,056.13 × 19% = 200.6647 → 200.67 PLN (rounded up to the grosz)
Nothing was paid in Germany, so the full 200.67 PLN is due in Poland.
What if tax was withheld abroad?
Some countries take their own tax from interest before it reaches you. Under art. 30a(9) of the PIT Act you can deduct that foreign tax from the Polish one — but only up to 19% of the income. Anything withheld above that is lost; you can't recover it on PIT-38.
Take the same payments, but suppose the bank's country withheld 10% from each one. Convert the withheld amounts at the same rates as the interest:
| Credited on | Withheld | Rate | In PLN |
|---|---|---|---|
| 31 March | 6.00 EUR | 4.1819 | 25.09 |
| 30 June | 6.24 EUR | 4.2362 | 26.43 |
| 30 September | 6.31 EUR | 4.2688 | 26.94 |
| 31 December | 6.42 EUR | 4.2293 | 27.15 |
| Total | 105.61 |
| Step | Calculation | Result |
|---|---|---|
| Polish tax at 19% | 1,056.13 × 19%, rounded up | 200.67 PLN |
| Tax paid abroad | 105.61 PLN | |
| Deduction cap (19% of the income) | 200.67 PLN | |
| To pay in Poland | 200.67 − 105.61 | 95.06 PLN |
The foreign tax fits inside the cap, so you deduct all of it. Remember that the tax base is still the gross interest — 1,056.13 PLN — not what landed in your account.
Exactly where these numbers go
Field numbers follow the Ministry of Finance brochure for the PIT-38 return for 2025.
Part G — tax to pay
| Field | What it is | No tax abroad | 10% withheld abroad |
|---|---|---|---|
| 47 | Flat-rate tax on foreign art. 30a(1)(1–5) income | 200.67 | 200.67 |
| 48 | Tax paid abroad (art. 30a(9)) | 0.00 | 105.61 |
| 49 | Difference to pay | 200.67 | 95.06 |
Don't use field 46 for foreign interest. It's for flat-rate tax that a payer should have withheld but didn't — the brochure explicitly excludes the amounts that belong in field 47.
If you also received foreign dividends, they go into the same three fields — add them to the interest amounts.
Do you need the PIT/ZG attachment?
No. PIT/ZG is for foreign income under art. 30b — capital gains and crypto. Interest is settled under art. 30a, and the foreign tax credit goes straight into field 48.
Common mistakes
- Declaring interest from a Polish bank. The bank already paid the tax. Declaring it again means paying twice.
- Assuming a foreign account is tax-free because nothing shows up in Twój e-PIT. The pre-filled return knows nothing about foreign accounts — the obligation is still yours.
- Entering the net amount. If tax was withheld abroad, the base is the interest before that tax.
- Converting the annual total at one rate. Each payment is converted at the rate from the business day before it was credited.
- Using the rate from the day of the payment. Always the preceding business day.
- Rounding to whole złoty. Interest tax is rounded up to the grosz.
- Deducting account fees. Art. 30a allows no costs at all.
Before you file
- Is the account actually abroad, with no Polish tax withheld?
- Did you list every interest payment for 2025, gross?
- Is each one converted at the NBP rate from the preceding business day?
- Is the tax rounded up to the full grosz?
- Is any tax withheld abroad in field 48 — and no higher than the Polish tax?
The return for 2025 is filed between 15 February and 30 April 2026, and the tax from field 49 is due by the same date.
This article is educational and is based on the Ministry of Finance information brochure for the PIT-38 return for 2025, art. 30a of the PIT Act and art. 63 § 1a of the Tax Ordinance. It is not tax advice. Whether and how much tax is withheld abroad depends on the country and on the double taxation treaty — check your statement.