Box 3 is the Dutch wealth tax covering savings and investments, and a second home or rental property sits inside it. You are not taxed on the rent you receive or the gain when you sell, but on an assumed return applied to the property's value on 1 January. For 2026 that assumed return is 6.00% for 'other assets' — the category holding property, shares and crypto — taxed at 36%, giving an effective annual cost of roughly 2.16% of the property's value, around €8,600 on a €400,000 holiday home. Bank deposits are assumed to return 1.28% and debts 2.70%; the tax-free allowance is €59,357 per person, or €118,714 for tax partners. The bill does not depend on performance: an empty holiday home and an identical one let all year are taxed the same. A government proposal to raise the rate to 7.78% and cut the allowance to €51,396 was withdrawn, but provisional 2026 assessments issued during 2025 were calculated using it.
Box 3 is the Dutch wealth tax that applies to savings and investments, and a second home or rental property sits squarely inside it. You are not taxed on the rent you receive or on the gain when you sell — you are taxed on an assumedreturn on the property’s value. In 2026 that assumed return is 6.00%for “other assets”, taxed at 36%, giving an effective annual cost of about 2.16% of the property’s value — roughly €8,600 a year on a €400,000 holiday home, payable whether or not the property earned you a cent.
Which box is your property in?
Dutch income tax is split into three boxes, and for property the distinction is decisive. The home you live in — your eigen woning — sits in Box 1, where mortgage interest is deductible and you pay eigenwoningforfait instead. Everything else — a second home, a holiday house, a property you rent out, a flat bought for a child — sits in Box 3.
Only one property can be your eigen woning at a time. The moment a property stops being your main residence, it moves to Box 3, and the mortgage on it stops being deductible. People who move abroad and keep their Dutch house are frequently caught by this.
How Box 3 actually works in 2026
Box 3 does not tax your actual income. It applies a fixed assumed return to the value of your assets on 1 January (the peildatum), then taxes that assumed return at 36%. There are three categories, each with its own assumed return:
| Category | Assumed return 2026 | What it covers |
|---|---|---|
| Bank deposits | 1.28% | Savings accounts, current accounts |
| Other assets | 6.00% | Property, shares, bonds, crypto |
| Debts | 2.70% | Deducted, above a threshold |
The bank-deposit and debt percentages are provisional and are finalised by the Ministry of Finance in early 2027. The 6.00% for other assets is already fixed. In 2025 it was 5.88%.
What a second home costs you each year
A second home is valued at its WOZ value on 1 January. Any mortgage on it is a Box 3 debt, deducted at the debt threshold (€3,800, or €7,600 with a tax partner). The tax-free allowance of €59,357 per person applies across your whole Box 3 position, not per asset — so if you already hold savings, the property is effectively taxed from the first euro.
| WOZ value on 1 Jan | Assumed return (6.00%) | Box 3 tax (36%) |
|---|---|---|
| €600,000 | €36,000 | €12,960 |
| €400,000 | €24,000 | €8,640 |
| €250,000 | €15,000 | €5,400 |
Gross of the tax-free allowance and any deductible mortgage on the property, both of which reduce the figure. Illustrative only — your own Box 3 position depends on all your assets together.
The important feature of this design: the bill does not depend on performance. An empty holiday home that earned nothing, and an identical one let all year, are taxed the same. So is a property that fell in value.
Check your 2026 provisional assessment
The government originally proposed raising the assumed return on other assets to 7.78% and cutting the tax-free allowance to €51,396. Both were withdrawn at parliament’s request — but provisional assessments issued during 2025 were calculated using them.
If you received a voorlopige aanslag for 2026 before the change, it may be overstated. Worth checking against the final figures rather than paying the number on the letter.
The tegenbewijsregeling — and why it often backfires on property
Following the Supreme Court rulings on Box 3, taxpayers can invoke the tegenbewijsregeling: if your actual return was lower than the assumed one, you are taxed on the actual figure instead. For savers with cash earning less than the assumed return, this is straightforwardly useful.
For property it frequently works the other way, and this catches people out. When you calculate your actual return, unrealised gains in value count as return — even though you have not sold and have not seen a cent. A second home that rose €40,000 in value over the year has, for this purpose, produced €40,000 of return on top of any rent.
In a rising market, that will often exceed the 6.00% assumed return, meaning the counter-proof route produces a higherbill than simply accepting the forfait. It is worth calculating both before choosing — and worth understanding that “prove your real return” is not automatically the taxpayer-friendly option it sounds like.
What this means for buy-to-let arithmetic
Box 3 is the reason Dutch rental yields need to be read net rather than gross. An effective 2.16% of gross property value comes off every year before maintenance, insurance, VvE contributions, management and vacancy. On a property yielding 6% gross, Box 3 alone consumes more than a third of it.
Combined with the 8% transfer tax investors pay on acquisition and the rent caps introduced by the Affordable Rent Act, the arithmetic of Dutch buy-to-let is materially different from a decade ago. None of that makes it a bad investment — it makes it one that has to be modelled net, with the tax in the model from the start.
What changes next
The government intends to replace this system with one based on actual returns from 1 January 2028, provided the legislation completes in time. Under such a system a second home would be taxed on the rent it genuinely earns and the gain genuinely realised, rather than on an assumed percentage. Until then, the forfait applies.
Everything above is the 2026 position. Box 3 has changed repeatedly in recent years and remains subject to litigation and legislative revision — check the current figures with the Belastingdienst before making a decision that depends on them, and take advice for anything involving multiple properties or a tax partner.
