Dutch personal income tax is commonly explained through three “boxes”. They are not three separate tax returns; they are categories inside the same income-tax system.
Box 1 — work and home
Box 1 includes employment income and several other forms of work/income, plus the tax treatment of an owner-occupied home and specified deductions. For most employees, this is the main box.
Box 2 — substantial shareholding
Box 2 applies to benefits from a substantial interest (aanmerkelijk belang), typically where you hold at least the statutory qualifying interest in a company. For 2026, Belastingdienst lists 24.5% up to €68,843 of taxable Box 2 income and 31% above that threshold.
Box 3 — savings and investments
Box 3 concerns income from savings and investments. For 2026, the tax rate on calculated Box 3 income is 36%. The 2026 tax-free asset allowance shown by Belastingdienst for the provisional assessment is €59,357 without a fiscal partner and €118,714 with a fiscal partner.
Important: Box 3 is legally and politically active, including the option/route around actual return (werkelijk rendement) and transitional calculations. Never reduce Box 3 to “36% of your savings”. The tax is applied to calculated Box 3 income, not simply the account balance.
Foreign assets still matter
If you are a Dutch tax resident, foreign bank accounts, investments or property can still belong in the return even where a tax treaty changes which country ultimately taxes the income or asset. Do not omit an item merely because it sits outside the Netherlands.