Essential Points
- Box 1800: It is your reference point for gains and losses from token sales or exchanges.
- Exchanges are taxed: Changing one asset for another creates an immediate tax obligation; don't wait to withdraw it from your bank.
- Staking and DeFi: They are not declared as income from movable capital.
- Total surveillance: Between form 721 and European regulations, the Tax Office has an almost exact picture of your movements.
Filing your tax return in Spain has never been a pleasant experience, but if you've also traded cryptocurrencies in the past year, the process can feel like a maze designed to trip you up. We're in the middle of the 2026 tax season, processing 2025 tax data, and the Tax Agency hasn't let up on its audits.
Are you clear on where every transaction goes? It's not just about pressing a button. The tax authorities want to know everything: from that swap you made between two tokens to the returns generated by staking, or, of course, if you have assets outside our borders.
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The treasure map: The key boxes of the tax return
Forget about looking for a single magic box that solves everything. Depending on how you've interacted with your digital assets, you'll have to jump from one section of Form 100 to another. The architecture of the financial system is changing, and the Spanish Tax Agency (AEAT) has adapted its forms so that not a single cent from the tokenized economy goes unreported.
The famous 1800 box and capital gains
If you've sold Bitcoin to get euros, or if you've exchanged one token for another, you've generated a change in net worth. This is where box 1800 comes into play.
This section is essential for most users. Here you must declare your net gain or loss. Remember that in Spain, exchanging one cryptocurrency for another is considered a barter, which triggers tax obligations even if you haven't transferred your funds to a traditional bank account.
- Box 1800: Used to declare capital gains and losses derived from the transfer of digital assets.
- Acquisition value: The price you paid for the asset, including fees.
Transfer value: The value at the time of sale or exchange, less the expenses of the operation.
Returns on movable capital: Staking and Farming
Are you one of those who prefers to let their tokens work? The interest you receive from DeFi protocols, staking, or even asset loans is not considered capital gains in the traditional sense, but rather income from movable capital.
In this case, the information is usually entered into different sections, generally in the boxes designated for "Other income from movable capital." It is vital to differentiate this because, although the taxable base for savings is usually the same, the source of the income determines how the tax authorities cross-reference the data with the exchanges.
| Concept | Tax Rating | Tax Base | Taxation Time |
|---|---|---|---|
| Staking (Rewards) | Performance of Movable Capital | Savings (19% – 28%) | At the time of payment |
| Airdrops | Capital Gain | Savings (19% – 28%) | At the time of reception |
| Token sale | Capital Gain/Loss | Savings (19% – 28%) | At the time of the exchange or sale |
| Loans (Lending) | Performance of Movable Capital | Savings (19% – 28%) | Upon receiving the interest |
Technical guide: How to declare step by step (HowTo)
Below, we detail the technical procedure to comply with your tax obligations using the Web Income Tax Simulator.
1. Prepare the list of transactions (Tax Reports)
Before accessing the AEAT website, download the reports from your platforms. By 2025, thanks to the MiCA standard and the Travel Rule, most entities will already be sending detailed information to the Tax Agency, so make sure your data matches what they already have.
2. Access to capital gains and losses
Within the draft, navigate to the section on "Capital gains and losses derived from the transfer of other assets."
3. Locate Box 1800
Specifically look for the section dedicated to virtual currencies. Here you will need to enter a breakdown of your transactions. The tax authorities allow you to group transactions if they involve the same asset, but ideally you should have the details in case you receive a request for information.
4. Enter acquisition and transmission values
Enter the total purchase cost and the total sale price. The system will automatically calculate the return. Remember that if the result is negative (losses), you can offset them with other gains over the next four years.
The new information models: 721 and more
We can't talk about the 2025 tax return without mentioning that transparency is now complete. If you have assets in foreign exchanges (like most of the big names in the sector) and they exceed €50.000, you should have already filed Form 721.
This form isn't for paying taxes, it's for reporting. But be aware: the Tax Agency uses this information to verify that what you declare on your tax return is consistent with your assets held abroad. Trying to hide balances in 2026 is basically like playing Russian roulette with a full reel.
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