Box 3 2026 — what expats in the Netherlands need to know

Published June 2026 · 6 min read

If you keep savings or investments in the Netherlands, you pay 36% tax on a deemed return every year — an assumed figure, not what you actually earned. This is Box 3, the Dutch wealth tax system, and it works very differently from what most expats are used to.

How Box 3 works

Currently, the Dutch tax authority does not tax your actual investment returns. Instead, it uses a "deemed return" — a fixed assumed percentage applied to your wealth — and taxes that. The deemed return differs depending on what you hold. In 2026, the rate for investments and other assets is 6%. The rate for savings (bank deposits) is set at approximately 1.28% for 2026 (preliminary — the definitive savings rate is only confirmed in early 2027 once actual market rates for the full year are known). Both are taxed at 36%.^[1]

So if you hold €100,000 in investments on top of the tax-free allowance (more on that below), the tax authority assumes you earned €6,000 from it and charges 36% of that — €2,160 — regardless of whether your portfolio actually went up, down or sideways.

The tax-free allowance

There is a tax-free threshold of €59,357 per person in 2026 (€118,714 for couples with a fiscal partner). Assets below this threshold are not subject to Box 3 tax at all. This is called the heffingsvrij vermogen. The threshold applies to your total Box 3 wealth — across all accounts and asset types combined, not per account.^[1]

What about debts?

Debts can reduce your Box 3 wealth, but two things matter. First, there is a threshold (drempel): only debt above €3,800 per person (€7,600 for fiscal partners) counts, and the part above it carries its own deemed rate — provisionally 2.70% for 2026.^[2] Second, the mortgage on your main home is not a Box 3 debt at all. Your own home and its mortgage sit in Box 1, where the mortgage interest is deductible and you declare the eigenwoningforfait. Only debts outside that — a consumer loan, or a mortgage on a second property — go into Box 3.^[2]

Work out your own Box 3 tax

The official method has several steps, so rather than walk through a static example, here is a calculator that does it for you. Change your situation, your investments and your savings (and a debt, if you have one) and it shows the full breakdown, step by step, with the Dutch terms the tax office uses.

This is the standard method. The two sections that follow — the counter-evidence rule and the year-end question — are the main exceptions to it.

What if your actual return was lower?

Since July 2025, there is a formal route to pay less. The tegenbewijsregeling (counter-evidence rule) allows you to declare your actual return to the Belastingdienst if it was lower than the deemed return, and be taxed on what you actually earned instead.^[3] As a rough guide, it is worth looking into if your real return for the year was well below the deemed 6% (or 1.28% on savings) — a year when your investments fell, or barely moved, is the obvious case. It takes careful record-keeping — interest, dividends, and realised and unrealised changes in value — and from 2025 you declare it directly in your annual return rather than on a separate form.

Can you just park it all in savings on 1 January?

A tempting idea: shift everything out of investments into a deposit account just before 1 January — the snapshot date the tax is measured on — so it is taxed at the low savings rate, then move it straight back afterwards. It does not work. There is an anti-arbitrage rule (peildatumarbitrage): if you switch money between categories within the three months around the snapshot date and reverse it, purely to lower the tax, the Belastingdienst disregards the move and taxes you as though you had never made it. The annual return (aangifte) even asks you directly whether you made transactions like this around the snapshot date.^[4]

A note on foreign assets

As a Dutch resident you declare your worldwide assets, so foreign bank accounts and foreign investments fall into Box 3 exactly like Dutch ones. Foreign property is an exception: a holiday home or rental abroad is still declared in Box 3, but tax treaties generally give the taxing rights to the country where the property sits, and the Netherlands then grants relief to avoid double taxation. The practical result is that you usually pay little or no Dutch Box 3 tax on the property's value — but the relief is calculated proportionally and is not always a complete offset, and the exact outcome depends on the specific treaty with that country. Worth getting checked rather than assumed.^[5]

The 30% ruling change

Until the end of 2024, expats with the 30% ruling could elect partial non-resident status, which kept foreign assets out of Box 3. That option was abolished from 1 January 2025.^[6] There is transitional relief, and this is the part that is easy to get the wrong way round: if you were already using the 30% ruling in the final pay period of 2023, you can keep electing partial status until the end of 2026. But if your ruling started from January 2024 onwards, the option is already gone — from 2025 you must declare your worldwide Box 3 assets, including UK ISAs, foreign savings accounts and overseas investment portfolios.^[6]

A UK ISA has no special status in the Netherlands. It falls within Box 3 and is taxed like any other investment account.

What changes in 2028

The deemed-return system is due to be replaced — from 2028 at the earliest — with a tax on actual returns, including unrealised gains, still at 36%. The legislation was submitted to parliament in 2025 and is still working its way through, so the detail and the timing may yet change.^[7] It would be a significant structural change, particularly for property holders and long-term investors, where unrealised gains would now be included.

What this means for expats

The interaction with UK ISAs, foreign investment accounts, and the post-2025 30% ruling change makes the picture more complicated than it is for a typical Dutch taxpayer. But the single idea worth taking away is simpler than any of the arithmetic:

Box 3 taxes what you hold, not what you earn — and that is the difference worth carrying into every decision about where your money sits.