In crypto, there is no such thing as a loss
That isn't wordplay — it's a real difference in how the rules are built.
For shares, the PIT-38 form has a dedicated field for a loss (field 29). For cryptocurrency, that field doesn't exist at all. Instead, if your costs exceeded your revenue, what you have is an excess of deductible costs, waiting for next year.
It sounds like a technicality, but the consequences are concrete — and, for an investor, better.
Why this beats a stock loss
Let's compare the two mechanisms. The rules for shares come from art. 9(3) of the PIT Act and are noticeably more restrictive.
| Stock loss | Crypto excess costs | |
|---|---|---|
| How much you can deduct in one year | 50% maximum of the loss | 100% |
| How long you can use it | 5 years, then it expires | Indefinitely |
| Field on the form | field 29 (loss) → field 30 | field 40 → field 38 of the next return |
For shares there's also a second option: a one-off deduction of up to 5,000,000 PLN in one of the five following years. Anything above that limit falls back to the general rule of 50% per year. For most retail investors this variant stays theoretical.
None of those restrictions apply to crypto. Excess costs carry over in full, for as long as it takes to use them.
When excess costs arise
There are two typical situations, and both count identically:
1. You sold for less than you paid. A loss in the everyday sense.
2. You bought but sold nothing. Your revenue is 0 and your costs are real. As far as the form is concerned, that's exactly the same situation.
The second case surprises a lot of people. If all you did through 2025 was accumulate BTC and you never sold any of it for fiat — you have excess costs and you should declare them.
The most expensive mistake: "I lost money, so I won't file"
This line of reasoning costs people more than any other.
The Ministry of Finance brochure states plainly that Part E is also completed by taxpayers who incurred costs even though they had no revenue from disposing of crypto that year.
Here's what happens if you don't file:
- The tax office has no record of your costs — it sees zero.
- Next year you sell at a profit and want to deduct those costs.
- They don't appear on any filed return, so there's nothing to carry forward.
- You pay 19% on the entire sale proceeds, not on the profit.
Excess costs carry forward only while they're declared on each successive return. Break that chain and they're gone.
Example: a bad year
2025 went badly.
- Bought: 1 BTC for 100,000 PLN
- Sold: that same BTC for 80,000 PLN
On the form it looks like this:
| Field | What it is | Amount |
|---|---|---|
| 36 | Revenue from disposing of crypto in 2025 | 80,000 |
| 37 | Costs incurred in 2025 | 100,000 |
| 38 | Costs from previous years | 0 |
| 39 | Income | 0 |
| 40 | Excess costs carried to next year | 20,000 |
Note this: field 39 gets 0, not "−20,000". The form has no provision for a negative amount — the difference goes into field 40.
That 20,000 PLN is your tax shield. Next year it will reduce your crypto income in full, with no 50% cap and no expiry date. Exactly how to move it across is covered in How to carry costs forward.
Excess costs only work inside their own bucket
Crypto costs reduce only future crypto revenue.
You cannot use a failed memecoin bet to reduce tax on:
- a gain from selling shares or ETFs (that's Part C),
- a dividend from a foreign company (that's Part G),
- your employment income.
It works the other way too — a stock loss won't help with crypto tax. They are two separate worlds that only meet when the final amount payable is totalled up.
Before you file
- Are you filing a PIT-38 even though you sold nothing?
- Is field 39 set to 0, with the excess in field 40?
- Do you have documentation for your costs, including ones from several years back?
- Do you remember to declare the excess every year until it's used up?
The return for 2025 is filed between 15 February and 30 April 2026.
This article is educational and is based on the Ministry of Finance information brochure for the PIT-38 return for 2025 and on art. 9(3) and art. 22(14) of the PIT Act. It is not tax advice.