What this article covers
In Crypto losses: it's not a loss, it's a cost we explain why excess costs are better than an ordinary loss. This article deals with something far more practical: how to physically move that amount from one return to the next without losing it on the way.
The whole mechanism comes down to one action: copying a single number from last year's form into this year's. The catch is that the field number you copy from changes depending on the year.
The chain of costs
Excess costs work like a relay. Each return has a field where the amount exits, and a field where it enters the following year.
Return for year N Return for year N+1
───────────────── ───────────────────
excess costs ──────▶ costs from previous years
(exit) (entry)
As long as you enter that number every year, the costs stay alive. Forget it once and the chain breaks — there's nothing left to carry.
The field numbers change every year
This is the point where most guides give up and say "look for the right field". You don't have to guess — the numbers are in the Ministry of Finance brochures.
| What you enter | 2024 form | 2025 form |
|---|---|---|
| Revenue from disposing of crypto | field 34 | field 36 |
| Costs incurred this year | field 35 | field 37 |
| Costs from previous years (entry) | field 36 | field 38 |
| Income | field 37 | field 39 |
| Excess costs (exit) | field 38 | field 40 |
The numbering shifted by two, because the 2025 form gained earlier fields.
What this means for the 2025 return: you take the amount from field 38 of the 2024 return and enter it in field 38 of the 2025 return. The fact that both are numbered 38 is pure coincidence — don't assume it will hold in future years.
When you file for 2026, you'll take the amount from field 40 of the 2025 return. You'll only learn the destination field number from the PIT-38 brochure for 2026, published around January 2027.
Example: two consecutive years
2024 — a rough start
You bought crypto for 50,000 PLN and sold only a small part of it for 10,000 PLN.
| Field (2024 form) | What it is | Amount |
|---|---|---|
| 34 | Revenue | 10,000 |
| 35 | Costs incurred in 2024 | 50,000 |
| 36 | Costs from previous years | 0 |
| 37 | Income | 0 |
| 38 | Excess costs | 40,000 |
Tax for 2024: 0 PLN. Field 38 holds 40,000 PLN waiting for next year.
2025 — the market recovered
You bought another 5,000 PLN worth and sold for 60,000 PLN.
| Field (2025 form) | What it is | Amount |
|---|---|---|
| 36 | Revenue | 60,000 |
| 37 | Costs incurred in 2025 | 5,000 |
| 38 | Costs from previous years — copied from field 38 of the 2024 return | 40,000 |
| 39 | Income = 60,000 − (5,000 + 40,000) | 15,000 |
| 40 | Excess carried to next year | 0 |
Tax: 15,000 × 19% = 2,850 PLN
What that was worth
| Without carrying costs | With carrying costs | |
|---|---|---|
| Tax base | 55,000 PLN | 15,000 PLN |
| Tax | 10,450 PLN | 2,850 PLN |
A difference of 7,600 PLN — for copying one number into the right box.
What breaks the chain
Excess costs exist nowhere except on your own returns. There's no register keeping track of them for you. You'll lose them if you:
- don't file a return for the year they arose,
- file a return but skip Part E, on the grounds that you "didn't sell anything anyway",
- forget to copy the amount in one of the following years,
- can't produce documentation showing where those costs came from.
That last one hurts the most. If you enter 40,000 PLN of prior-year costs on your 2025 return, you have to be able to show statements and confirmations from 2024 or earlier. Exchanges shut down and accounts get closed — export your history before it's too late.
Common misunderstandings
- "I have to use the costs within 5 years." No. The five-year limit applies to stock losses. Crypto excess costs have no expiry date.
- "I can only deduct half per year." No. The 50% cap also applies to shares. Crypto is deducted in full.
- "I'll apply my crypto loss to my shares." No. Separate buckets, and they don't mix.
- "Swapping BTC for USDT is a sale, so I have revenue." No. Crypto-to-crypto is neutral — details in Crypto gains.
Before you file
- Do you have last year's return to hand, and did you read the right field from it?
- Did you check the field number in the brochure for the correct year?
- Did last year's "exit" field make it into this year's "entry" field?
- Have you kept documentation for the prior-year costs?
- Are you filing Part E even in years with no sales?
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 brochures for the PIT-38 returns for 2024 and 2025 and on art. 22(14) of the PIT Act. It is not tax advice. Always verify field numbers in the brochure for the relevant year's form.