Declaring crypto in the Netherlands in 2026.

For most private crypto holders, 1 January still serves as the reference date for the Box 3 asset position. On that date, you add up the value of holdings on exchanges, in hardware wallets and in software wallets, converted to euros at the market price prevailing then.

What happens to the price for the rest of the year generally does not change the tax base for that year. Keep careful records of the price and source you used, so you can substantiate it later if the Tax Administration asks.

There is no legally prescribed source for valuing crypto, but in practice the price on a recognised exchange, or a representative average, on the reference date is generally used, converted to euros.

For tokens not listed on major exchanges, or illiquid altcoins, determining a market value can be harder. In that case, document how you arrived at the value used, for example via a price aggregator, so your approach is traceable.

Many Dutch crypto holders use international platforms not based in the Netherlands. This does not change the filing obligation: balances on a foreign exchange or in a foreign wallet app also count towards your Box 3 assets if you are taxable in the Netherlands.

Some foreign platforms do not offer annual statements in a format that maps directly onto the Dutch return. It is then up to you to derive the euro value on the reference date from transaction history and price data, underlining the importance of good record-keeping throughout the year.

In practice, the burden of proof for the accuracy of your return largely rests with you. This means that in the event of an audit you must be able to show how you arrived at the declared value: exchange statements, wallet addresses, and a traceable calculation of the euro value on the reference date.

A well-organised administration, for example built up from exchange exports and a portfolio tracker, saves time and discussion if the Tax Administration asks for clarification.

It happens that people only later discover they did not, or only partially, declared crypto in previous years, for example after rediscovering an old wallet. The Netherlands has a voluntary disclosure scheme that allows you to correct an earlier return.

The exact consequences and conditions depend on the circumstances and the rules in force at the time. If in doubt, contact a tax adviser promptly; proactively correcting is generally viewed more favourably than waiting for the Tax Administration to discover it itself.