Fiscal partners in the Netherlands

What is a fiscal partner in the Netherlands?

A fiscal partner is someone the Belastingdienst lets you share certain tax items with.¹ It affects the parts of your return you can share.

The Dutch call it fiscaal partnerschap. It changes how Box 3, several deductions and some tax credits work for the two of you. You do not sign up for it. The Belastingdienst decides it from your situation.

Two things create it. Marriage or a registered partnership makes you partners at once. Living together can make you partners too, once you meet one extra condition. We explain both below.

It is not the same as a toeslagpartner, which covers allowances under separate rules. We explain the difference later.

Take Camila and Paulo. They moved in together this year and bought their flat together. They wonder whether that changes their tax. We follow them through this page.

When do you become fiscal partners?

You become partners automatically if you marry or enter a registered partnership.¹ You are then partners from that date. Were you already registered together earlier that year? Then your partnership counts from your registration date.

If you live together, one more thing has to be true. You must be registered at the same address and meet one condition. Owning the home you both live in counts. So do a cohabitation agreement, a child in the household, or being partners in each other's pension scheme.

Partnership starts on the date you both registered at that address.¹ Registered together in an earlier year? Then it starts on 1 January of the year you meet a condition.¹ Did you become partners by living together? Then partnership ends once one of you deregisters from that address. Marriage or a registered partnership does not end that way.

Camila and Paulo are registered at their new address and own it together. So they became fiscal partners on the day they both registered there.¹ A few living situations have their own rule. Living with your parent or your adult child only counts once you are both 27 or older. Does your partner still live outside the Netherlands? Then have your partnership checked before you file. The table below sets out the routes.

What changes once you are fiscal partners?

You share several parts of your tax return as partners. Some of it helps you, some of it needs a second look.

Your Box 3 tax-free allowance doubles. On your own you each have €59,357 in 2026. Full-year partners are couples who were fiscal partners for the whole tax year. Together, as full-year partners, you share €118,714.¹ The Belastingdienst taxes savings and investments above that. Were you partners for only part of the year? Then you can choose together to count as full-year partners.¹ Camila and Paulo became partners this year, so they use that choice.

You can also divide shared income and deductions between you. Any split that adds up to 100% is allowed. Picking the best split is its own subject. We explain how in our guide to the tax-partner allocation.

One thing can work against you. Some deductions only count above a threshold, and that threshold is based on your joint income. So a healthcare cost that Camila could deduct on her own can fall below the line once Paulo's income is added.¹ The table follows the figures.

No fiscal partner, but a shared home?

Then you each deduct only your own share of the home.² One of you paying the whole mortgage does not change that.

The Belastingdienst has a name for this: co-owners who are not fiscal partners. You own a home together, but you are not fiscal partners. A parent and a child under 27 who co-own their home are one example. You can only deduct interest if the home is your main residence.

Each owner deducts the mortgage interest for their own share of the debt. The eigenwoningforfait follows your ownership share too. That is a small amount added for living in your own home. The same goes for any ground lease.² Say one owner holds three-quarters and the other one-quarter.

So the owner with three-quarters deducts three-quarters of the interest, and reports three-quarters of the eigenwoningforfait. The other quarter follows the second owner. Getting each share right is where a second look pays off.

What does this mean for you?

You now know when partnership starts and what it changes. The next step is your own situation.

Check whether you became fiscal partners and from which date. Look at your combined Box 3 total, not just your own. Living together without being partners? Then split every home cost by ownership share. Moving in this year? Then a toeslagpartner may already count for your allowances.

Camila and Paulo start with their partnership date, then check their joint Box 3 total. You can see how we handle a full return in our guide to the Dutch tax return. It is part of the wider Dutch tax system.

Our page about tax partnership explains who counts as your partner and what that changes.