How Box 3 Wealth Tax Works in the Netherlands
Box 3 is the Dutch income tax on savings and investments. Unlike Box 1 (employment income) which taxes actual income, Box 3 taxes a deemed return — a fictional percentage that the Belastingdienst assumes your assets are earning, regardless of what they actually earned.
The deemed return differs by asset type. Bank savings are taxed at a low rate (1,37% in 2025) because savings accounts typically earn little. Investments and other assets are taxed at a higher rate (5,88% in 2025) because the Belastingdienst assumes they earn more. The resulting deemed income is taxed at 36%.
The Calculation — Step by Step
Step 1: Total Assets = Savings + Investments + Other Assets
Step 2: Deductible Debts = Total Debts − Debt Threshold (€3.800 single / €7.600 partners)
Step 3: Capital Yield Tax Base = Total Assets − Deductible Debts
Step 4: Taxable Base = Capital Yield Tax Base − Tax-Free Allowance
Step 5: Asset Shares = Savings ÷ Total Assets and Investments ÷ Total Assets
Step 6: Deemed Income = (Taxable Base × Savings Share × Savings Rate) + (Taxable Base × Investment Share × Investment Rate)
Step 7: Box 3 Tax = Deemed Income × 36%
Source: Belastingdienst.nl official Box 3 calculation method. Values on 1 January of the tax year.
The Actual Return Option (OWR)
Since the 2021 Supreme Court ruling, taxpayers can report their actual return instead of the deemed return using the Opgaaf Werkelijk Rendement (OWR) form. The Belastingdienst will use whichever is more favourable. If your investments had a poor year — or your savings interest was very low — the actual return method may significantly reduce your tax bill. This calculator uses the standard deemed return method as the baseline.
Box 3 Rates — 2025 vs 2026
| Parameter | 2025 | 2026 |
|---|
| Tax-free allowance (single) | €57.684 | €59.357 |
| Tax-free allowance (fiscal partners) | €115.368 | €118.714 |
| Deemed return — bank savings | 1,37% | TBC (provisional) |
| Deemed return — investments | 5,88% | 6,00% |
| Deemed return — deductible debts | 2,70% | TBC |
| Debt threshold (single) | €3.800 | €3.800 |
| Tax rate on deemed income | 36% | 36% |
The 2026 voorlopige aanslag sets the investment deemed return at 6,00%, down from 5,88% in 2025. The savings rate falls to 1,28% from 1,37%. Final rates may differ slightly from the provisional aanslag.
Frequently Asked Questions
What assets fall under Box 3?+
Box 3 covers bank savings, stocks, bonds, ETFs, cryptocurrency, a second home or holiday home, savings in foreign accounts, loans you have made to others, and most other assets not covered under Box 1 or Box 2. Your primary residence and its mortgage are excluded — they fall under Box 1. Company shares where you own 5% or more fall under Box 2.
How does the fiscal partner split work?+
Fiscal partners can divide Box 3 items between them in the return. Box 3 is taxed at a flat 36% rate regardless of individual Box 1 income — it does not interact with the income tax brackets. Always verify with a tax adviser what the optimal allocation is for your specific situation.
Is my mortgage deductible in Box 3?+
No. Your mortgage on your primary residence is a Box 1 debt and is not deductible in Box 3. Only debts that are not associated with your primary home are deductible in Box 3, and only the portion above the threshold of €3.800 (single) or €7.600 (fiscal partners) can be deducted.
What is the Actual Return (OWR) option and should I use it?+
The Opgaaf Werkelijk Rendement (OWR) allows you to report what your assets actually earned instead of the deemed return. The Belastingdienst calculates both and applies the lower result. If your savings earned minimal interest or your investments lost value, the actual return method is likely more favourable. It includes interest received, dividends, rental income, and realised gains, but also unrealised gains in most cases. A tax adviser can calculate which method benefits you more before you file.
How does the 30% ruling affect Box 3?+
From 2025 onwards, employees with the 30% ruling must declare their Box 3 assets and pay Box 3 tax. Previously, holders of the 30% ruling could opt for partial non-resident status and were largely exempt from Box 3 on foreign assets. Employees who had the 30% ruling in 2023 fall under transitional rules and may still benefit from the exemption until 2027.