The second date
The prize is taxed once, and the coin you kept is counted again on 1 January
Gambling tax measures a calendar month. Box 3 measures one instant a year: the value of what you own at the start of it, under article 5.2 of the Wet inkomstenbelasting 2001. A coin won in March and still held on 1 January passes through both, and the two use different figures for the same coins.
Two taxes, and only one of them is about gambling
A person who has read about kansspelbelasting sometimes thinks the tax question is closed. It is closed for the prize, and the prize is not the only thing the tax system looks at.
Gambling tax is an event tax. It attaches to what was won, and for a provider without a Dutch permit it is the winner who files it, on a base measured per calendar month, at the rate in article 5, first paragraph of the Wet op de kansspelbelasting. All of that is set out on the gambling tax page.
Box 3 is not an event tax at all. It taxes a position: what a person holds at one moment, once a year. Nothing in it asks where the holding came from.
Which is why a win can pass through both, and why the two never produce the same number.
What box 3 measures, and at exactly which instant
Chapter 5 of the Wet inkomstenbelasting 2001 covers income from savings and investments. Article 5.2 builds the taxable benefit from the position at the beginning of the calendar year, which in practice means one date: 1 January.
That single date does most of the work. It means the tax has no interest in what a balance did during the year — how many times it was staked, how far it rose, how far it fell. What counts is what was there when the year started.
Article 5.19, first paragraph, says how the holding is valued: at its value in economic traffic, which for a coin with a market price is the market price. Article 5.5 sets an exempt amount below which the box produces nothing. Under the bridging regime that has applied since 2023, the calculation sorts a holding into categories — bank deposits, other assets, debts — and a crypto-asset belongs to the middle one, other assets, with a percentage fixed for the year rather than an actual return.
Three articles, one date. That is the whole architecture, and it does not mention gambling anywhere.
Why the same coins produce two different figures
Take a win in March, kept in the same coin, still held at the end of the year.
Gambling tax looks at March. Its base is the difference between what was won and what was staked within that calendar month, valued when the prize became payable. That figure is fixed by the events of March and never moves again.
Box 3 looks at 1 January of the following year, and values the holding on that day. Between March and January the market has done whatever it has done, and the number entering box 3 is the one that survived that.
The gap between the two figures can run in either direction, and neither statute treats the other's figure as relevant. Two measuring moments, two valuations, one balance. This is the point at which the choice between a stablecoin and a volatile coin stops being a question about the casino and becomes a question about the calendar.
A win spent, converted and gone before the year turns never meets the second moment at all. That is not a strategy and is not offered as one; it is simply what the statute measures.
What this page does not print, and why
No percentage, and no exempt amount in euro.
Both are set per year. The forfaitary percentages for the categories in article 5.2 and the exempt amount in article 5.5 are fixed for each calendar year separately, and the table for the current year was not read for this page. On a site whose rule is that every figure carries the clause it came from, printing a percentage from memory is worse than printing none: a stale figure looks exactly like a current one.
So this page prints the articles and the date, which do not change from year to year, and sends a reader who needs the amounts to the source that publishes them.
The same rule is applied to the operator side of the table: an empty cell means the document was looked at and the figure was not found, not that the figure is zero.
Where the two taxes touch each other
They touch in exactly one place: the balance.
Gambling tax is filed and paid on the prize, and whatever is left after that is the holding box 3 will look at. Paying the first one reduces what enters the second, in the ordinary way that paying anything reduces what is left. There is no offset, no credit, and no provision in either statute that reads across to the other.
There is also a practical link that has nothing to do with law. A withdrawal that arrives late — because a document request or a published ceiling stretched it across weeks — can land on the other side of a year boundary, and the year in which a coin arrives decides which 1 January it is present for. The ceiling clauses and what they do to a large payout are the part of an operator's terms that can move that date.
What this page is not
It is not tax advice, and it is not a substitute for the Belastingdienst or for an adviser. It sets out which statute governs which moment, with the article numbers, so that a reader can check both against the text rather than against a comparison page.
It also makes no claim about how any of this is enforced, how holdings are traced, or what is reported to whom. Nothing on this site has been checked against enforcement practice, and the subject here is the wording of the statutes and the dates they fix.