Most common mistakes when declaring cryptocurrencies in the IRPF
After analyzing thousands of crypto tax returns, these are the most frequent mistakes that can cost you penalties or lead to paying more than you should.
Error 1: Not declaring crypto-to-crypto exchanges
Many investors believe they only need to declare when "cashing out to euros." Incorrect. Every exchange between cryptocurrencies (BTC for ETH, ETH for SOL…) is a disposal that generates a taxable event at the moment of the swap.
Error 2: Using average price instead of FIFO
The AEAT requires FIFO. If you calculate your gain using the average purchase price, the result will be different (and wrong). This can lead to both overpaying and underpaying — and the AEAT will always verify the method.
Error 3: Not including commissions
Purchase commissions reduce the future acquisition cost (they increase the gain if forgotten). Sale commissions reduce the transfer value. Forgetting commissions can mean paying more taxes than necessary.
Error 4: Treating self-transfers as sales
If you export the history from an exchange and do not match the transfers to your other wallets, they appear as sales without a corresponding purchase, triggering huge false gains.
Error 5: Not declaring staking and airdrops
Staking rewards and airdrops are reportable income in the year they are received, not when they are sold. Omitting them is tax evasion, even if it is unintentional.
Error 6: Not carrying forward losses from previous years
Crypto losses can be carried forward for up to 4 years. If you had losses in 2022 and did not offset them correctly, you might be overpaying in 2023, 2024, and 2025.
Error 7: Mixing income from the general tax base and the savings tax base
Gains from crypto transfers go into the savings tax base. Staking rewards and airdrops without consideration may go into the general tax base. Mixing them in the wrong boxes generates errors in the tax assessment.
Error 8: Not filing Forms 172 and 173
These are mandatory informative returns since 2023. Failing to file them, even if you do file your IRPF, can lead to additional penalties and attract the attention of the AEAT.
Error 9: Ignoring cryptos in DeFi and private wallets
Many users only report what is in centralized exchanges, forgetting their hardware wallets, DeFi positions, or tokens in protocols. The AEAT is increasingly cross-referencing blockchain data.
Error 10: Waiting until the last minute
Data from exchanges takes time to export and process. Starting in April is too late if you have hundreds or thousands of transactions. Prepare the information starting in January.
Conclusion
Most of these errors are avoided with three things: a complete record from day one, using the FIFO method correctly, and a specialized tool that automates the calculation and generates the report ready for the tax return.