Box 3 in 2026: how your savings and investments are taxed

The tax-free amount

Box 3 is the part of income tax that covers savings and investments, worked out by the Belastingdienst (the Dutch tax office). It looks at what you own on 1 January, not at what you earned during the year. In 2026 the first €59,357 a person has is free of it. Fiscal partners, such as a married couple, have €118,714 together. With €150,000 in a savings account and no partner, the tax comes to €417 for the year.

Box 3 covers savings and cash, shares, funds and bonds, a second home and a home you rent out. Your own home and the pensions you build through work aren't counted, and neither is a lijfrente while it builds up.

If your savings and investments stay below the tax-free amount, you pay no Box 3 tax at all. A single person with €50,000 in savings pays nothing in 2026.

The assumed returns

Box 3 is a tax on what you hold, so a low return doesn't lower the bill. A savings account that paid nothing in 2026 would still count as earning 1.28%. The Belastingdienst assumes a return on each kind of wealth and taxes that:

Only the rates for savings and debts are provisional. The Belastingdienst fixes them in early 2027. The rate for investments is final for 2026. If you have both savings and investments, each gets its own rate, and the two together make up one assumed return.

The rates are for 2026. The Belastingdienst sets them again each year, so the rates for later years may differ.

How the tax is worked out

The tax-free amount isn't taken off one kind of wealth first. It takes the same share off all of it, so every kind of wealth is reduced in the same proportion. The calculation has four steps:

1. Multiply each kind of wealth by its assumed return, and take off the return on any debts above the threshold.
2. Work out how much of your wealth is above the tax-free amount, as a share. Take any debts above the threshold off your wealth. Take the tax-free amount off that, and divide the result by your wealth after debts.
3. Apply that share to the assumed return. That's the return you're taxed on.
4. Tax that return at 36%.

Only the balances on 1 January count, at their value that day: what's in your savings accounts, and what your investments are worth. Debts count too, but only the part above €3,800 a person. A single person with €100,000 in savings and a €10,000 debt pays €147 for the year. The €6,200 of debt above the threshold reduces the base, and it's taken off the return at 2.7%.

The same money costs more tax as investments than as savings, because investments are assumed to return more. One person with €150,000 in investments pays €1,957 a year. Fiscal partners with €150,000 between them pay €675, because each has a tax-free amount.

Fiscal partners

Fiscal partners, such as a married couple or registered partners, file together. Each partner has a tax-free amount, so together they have €118,714. Their debt threshold is twice the one for a single person.

On their joint tax return they can divide their savings and investments between them however they like, as long as the total stays the same.

If your actual return was lower

Since 1 July 2025 you can ask the Belastingdienst for money back if you paid too much Box 3 tax. You do that by showing your actual return on the form "Opgaaf werkelijk rendement" (OWR). The scheme comes from the Wet tegenbewijsregeling box 3, and it applies until the new system starts.

You report the actual return on all your savings and investments together. You can't report it for only part of them. Keep the figures for every account and investment, because the return is worked out on the total. If your actual return was lower than the assumed one, you get back the tax you paid on the difference.

How Straks counts Box 3

Each year the calculator takes the Box 3 tax off your savings and investments, at the 2026 rules. It uses the same assumed rates as the tax return, not your actual return. It does this every year until your plan ends at 90, so your savings have less left to pay for your retirement. Your home and its mortgage aren't in Box 3, so the calculator doesn't count them there.

If you add your partner in the calculator, Straks counts you as fiscal partners, with two tax-free amounts and two debt thresholds. On your own, you get one of each.

Checking your Box 3 tax

Your provisional assessment (voorlopige aanslag) shows the Box 3 tax the Belastingdienst expects for the year. Compare the balances it uses with your own on 1 January, and correct anything that's wrong when you file.

What changes from 2028

The government wants to tax the actual return instead, from 1 January 2028. The Tweede Kamer (House of Representatives) has passed the bill, but the Eerste Kamer (Senate) hasn't voted on it. On 30 June 2026 the Senate put off its vote until the government's changes to the bill (a novelle) are dealt with. So 2028 isn't certain.

The bill mainly taxes the growth in value of your savings and investments each year, whether or not you sell. The changes the government has announced move towards taxing profit instead.

Until a new law is in force, the rules above apply. The calculator uses the 2026 rules for every year ahead, so it doesn't yet show the reform. We'll update this guide when the law changes.