Marriage and taxes: the marriage penalty, splitting and the second-earner deduction

Joint taxation: the basic principle

In Switzerland, married couples and registered partnerships are taxed jointly. Both incomes and assets go into a single tax return. Because income tax is progressive — higher incomes are charged at higher rates — the combined income would, without correction, slip into a higher schedule band than two separate incomes.

This is exactly where the much-discussed marriage penalty comes from: two people each earning CHF 80,000 can, as a married couple, pay more tax than two single people with the same total income — especially in the direct federal tax.

How the cantons counteract it

So that joint taxation does not systematically penalise couples, the Confederation and the cantons apply various mechanisms:

• Full splitting — The total income is halved (divided by two) for determining the rate, and the rate thus obtained is then applied to the whole income. Married couples thereby benefit from the lower rate.
• Partial splitting — Like full splitting, but with a different divisor (for example 1.9 instead of 2.0).
• Married-couple schedule — A separate, flatter schedule for married people instead of a splitting (as in the direct federal tax).
• Family quotient — In the canton of Vaud, income is divided by a quotient that also takes children into account.

In our cantonal tax comparison, you can switch between “single” and “married” and see immediately how strongly each canton eases the progression for married couples.

The second-earner deduction

If both partners are in gainful employment, the Confederation and most cantons grant a second-earner deduction on the lower of the two incomes. It is meant to partly offset the additional burden of joint taxation. The deduction is especially relevant when both earn roughly the same — precisely the constellation in which the marriage penalty bites hardest.

When marriage is tax-favourable — and when not

As a rule of thumb:

• One main earner, a low or no second income: marriage is usually favourable for tax. Splitting and the married-couple schedule clearly lower the progression on the high income.
• Two similar incomes: here the marriage penalty looms, above all in the direct federal tax. The second-earner deduction eases it but does not always cancel it out.

Important: no one decides their marital status for purely tax reasons. But it helps to know the order of magnitude — precisely with two good incomes, the difference can amount to several thousand francs a year.

What this means for your planning

Marriage changes not only the schedule but also your deduction options and your AHV situation. Two concrete steps:

1. Calculate the scenario: in the cantonal tax comparison, compare your burden as “married” with the sum of two “single” calculations.
2. Use the deductions: both partners can pay separately into pillar 3a and thereby lower the joint taxable income twice over.

Note: general information, not tax advice. The exact splitting and deduction rules differ by canton and change with ongoing reforms (such as the discussions on individual taxation at federal level).