Tax and Box 3
You pay tax on your assets in Box 3. But how much tax do you pay, for example, on your savings, investments and a second home (holiday home) in 2026? And what exactly do you enter in Box 3? We are happy to offer some advice.
Supreme Court ruling: Box 3 is still discriminatory
The Supreme Court has ruled that you never pay more tax in Box 3 than the tax on the actual return you achieved. At the end of 2024, the Dutch Tax and Customs Administration sent over 2.6 million letters to people who are eligible for restoration of rights for tax in Box 3. If you have paid tax on the basis of a flat-rate return (the flat-rate savings variant) assumed by the Dutch Tax and Customs Administration and you are eligible for restoration of rights, you will pay less tax if you can demonstrate that the return on your savings and investments was lower. The Dutch Tax and Customs Administration has developed a counter-evidence form (Statement of Actual Return) which you can use to calculate your actual return. This form has now gone ‘live’.
Asset categories with assumed (flat-rate) returns
| Category | Flat-rate return |
| Bank and savings balances | Based on the current interest rate for savings: this is 1.28% in 2026* |
| Investments / other assets | Based on the long-term average return on investments in real estate, shares and bonds: this is 6.00% in 2026 |
| Debts | Based on the current mortgage rate: this is 2.70% in 2026* |
* The flat-rate return for savings and debts is announced after the end of each calendar year. All flat-rate returns for 2025 have now been determined. These are 1.37% for bank balances, 5.88% for investments / other assets, and 2.70% for debts.
For interest on bank balances, the applicable rate is the ‘bank interest rate on deposits of households in the Netherlands, redeemable at notice’. If the flat-rate return for savings turns out to be higher than this applicable rate, your final income tax assessment might state that you have to pay tax. The percentages used are estimates made by CPB (Netherlands Bureau for Economic Policy Analysis).
Composition of savings, other assets and debts
The flat-rate savings variant takes into account the actual composition of your savings, debts and other assets in Box 3 on the reference date, January 1. This forms the tax base. Tax-free assets of €59,357 apply (in 2026; for two tax partners tax-free assets of €118,714 apply). The result - the flat-rate return - is then taxed at 36% (2026).
Step-by-step plan for calculating tax in Box 3
- Determine the capital yield tax base (assets minus debts) and divide the Box 3 assets into three asset categories:
a. bank and savings balances
b. investments / other assets
c. debts (less the debts threshold of €3,800 per taxpayer)
Deduct the tax-free assets from the capital yield tax base to determine the tax base for savings and investments. - Calculate the taxable return. This is the sum of the flat-rate returns of the three asset categories.
- Calculate the rate of return. This is the total flat-rate return (step 2) divided by the capital yield tax base calculated in step 1 (i.e., before the deduction of tax-free assets).
- Calculate the benefit from savings and investments. This is the tax base for savings and investments (step 1) x the rate of return calculated in step 3.
- The Box 3 tax for 2026 is 36% of the benefit from savings and investments (step 4).
Example calculation
Anneke is single and has a bank account with a balance of €100,000 on January 1, 2026. In the spring of 2025, she bought a holiday home valued at €500,000 for property tax purposes. She borrowed €450,000 for this transaction. We do not take the debts threshold into account.
The calculation below follows the steps set out above.
Step 1
Anneke’s Box 3 assets amount to:
| - Bank and savings balances | € 100,000 |
| - Investments / other assets | € 500,000 |
| - Debts | € 450,000 -/- |
| Capital yield tax base | € 150,000 |
| - Minus: tax-free assets | € 59,357 -/- |
| Tax base for savings and investments | € 90,643 |
Step 2
The taxable return is:
| - Bank and savings balances | €100,000 x 1.28% = | €1,280 |
| - Investments / other assets | €500,000 x 6.00% = | €30,000 |
| - Debts | €450,000 x 2.70% = | - €12,150 |
| Taxable return | €19,130 |
Step 3
The rate of return is: €19,130 / €150,000 = 12.75%
Step 4
The benefit from savings and investments is: €90,643 x 12.75% = €11,556
Step 5
Anneke’s Box 3 tax is: €11,556 x 36% = €4,160.
For tax partners, the amount of tax-free assets is doubled.
Box 3 up to 2028:
If you can prove that your actual return is lower than the predetermined flat-rate return, you pay tax on your actual return.
Box 3 as of 2028:
On 12 February 2026, the House of Representatives adopted the legislative proposal for the Box 3 (Actual Return) Act. The plan is to levy tax on assets that is in line with the actual return achieved. The new law is expected to enter into force in 2028.