First: you probably didn't pay any
This guide is about tax paid abroad on a gain from selling — shares, ETFs, bonds, derivatives or crypto. It's rarer than most people think.
Most countries don't tax a foreign investor's gains from selling shares; a sale through a US broker, for example, usually comes with no US tax at all. Tax on dividends and interest withheld abroad is a different thing, with its own fields (47–49) and no PIT/ZG. That's covered in ETF income and dividends and Interest from a foreign savings account.
But if a foreign country did tax your gain, Poland lets you deduct that tax — up to a limit. Here's how.
What the law says
The Ministry of Finance brochure describes two fields that work the same way:
| Field | For | Legal basis |
|---|---|---|
| 34 (Part D) | Gains on shares and other securities | art. 30b(5a) and (5b) |
| 44 (Part F) | Gains on crypto | art. 30b(5e) and (5f) |
You fill them in if you earned that kind of income abroad, or in Poland and abroad. You enter the foreign tax converted into złoty — at the NBP average rate from the last business day before the day the tax was paid (art. 11a).
There's one limit, and it's the whole point of this article:
The deduction can't be more than the part of the Polish tax that proportionally falls on the income earned abroad.
The limit, step by step
The brochure gives the formula:
limit = Polish tax on all income × foreign income ÷ total income
Where:
- Polish tax on all income is 19% of your total income from Poland and abroad — field 33 (or 43 for crypto),
- foreign income is the income earned abroad (revenue minus costs),
- total income is the income from Poland and abroad together.
You then deduct whichever is lower: the tax you actually paid abroad, or the limit.
If you only had foreign income, the formula simplifies: the limit is just 19% of that income.
A worked example, step by step
In 2025 you had:
- 6,000 PLN of income from shares sold through a Polish broker,
- 4,000 PLN of income from shares sold abroad, on which that country took 1,000 PLN of tax (already converted into złoty).
Polish tax on everything (Part D)
| Field | What it is | Amount |
|---|---|---|
| 28 | Total income: 6,000 + 4,000 | 10,000 |
| 31 | Tax base | 10,000 |
| 33 | Tax: 10,000 × 19% | 1,900 |
The limit
1,900 × 4,000 ÷ 10,000 = 760 PLN
The deduction
You paid 1,000 PLN abroad, but the limit is 760 PLN. You deduct the lower amount.
| Field | What it is | Amount |
|---|---|---|
| 33 | Tax | 1,900 |
| 34 | Foreign tax deducted (the limit) | 760 |
| 35 | Tax due | 1,140 |
The other 240 PLN isn't deductible in Poland. The foreign rate was higher than the Polish 19%, and Poland only gives back up to its own tax on that income.
What if the foreign tax had been lower?
Had the foreign country taken only 300 PLN, that's below the 760 PLN limit, so you'd deduct all of it:
1,900 − 300 = 1,600 PLN in field 35.
Shares and crypto never mix
Field 34 and field 44 are calculated separately. Foreign tax on a crypto gain goes in field 44, and its limit is worked out only from your crypto income in Part F — not from the total of shares and crypto together. The same goes the other way.
Do you need a PIT/ZG?
PIT/ZG is an attachment that reports foreign income and the tax paid on it. According to the brochure:
- you file it if you had foreign income under art. 30b (Parts D and F) that's taxed in Poland using the deduction method — that is, you're deducting foreign tax in field 34 or 44,
- you file one PIT/ZG per country,
- in Part L you state how many you're attaching.
So: foreign tax deducted in field 34 or 44 → PIT/ZG for each country.
What if a gain was earned abroad but no tax was paid there? Then there's no foreign tax to deduct. Some tax programs still produce a PIT/ZG with zero tax; filing one does no harm.
Dividends and interest in Part G don't need a PIT/ZG at all.
When foreign tax can't be deducted
This part comes from the PIT Act rather than the brochure. Art. 30b(5a) allows the deduction where the income is taxed abroad and the double tax treaty doesn't say otherwise.
Many treaties give the right to tax gains from selling shares only to the country where you live — Poland. If a foreign country withheld tax anyway, the treaty may not let you deduct it here. In that case the way to get it back is usually a refund claim with the foreign tax authority, not field 34.
Before deducting, check two things:
- Did the foreign country have the right to tax this gain under the treaty?
- Do you have proof — a broker statement or tax certificate showing the tax actually paid?
Common mistakes
- Deducting the full foreign tax without applying the limit.
- Putting dividend tax in field 34. Dividend and interest tax goes in field 48, Part G.
- Converting at the wrong rate. Use the NBP rate from the business day before the tax was paid — not before the sale.
- Mixing shares and crypto when working out the limit.
- Forgetting the PIT/ZG — one per country.
- Deducting tax the treaty didn't allow the other country to take.
Before you file
- Was tax actually withheld or paid abroad on a gain from selling — not a dividend?
- Does the treaty let that country tax the gain?
- Is the foreign tax converted at the NBP rate from the business day before it was paid?
- Have you applied the limit — Polish tax × foreign income ÷ total income?
- Shares in field 34, crypto in field 44, each with its own limit?
- A PIT/ZG for each country, and the number in Part L?
This article is educational and is based on the Ministry of Finance information brochure for the PIT-38 return for 2025 and on art. 11a and 30b(5a)–(5f) of the PIT Act. It is not tax advice.