Why it exists
Swiss tax is progressive — a higher income lands you in a higher rate band. When two spouses' incomes are summed on a joint return, the couple lands in a higher band than either spouse alone would. Without correction, the joint tax bill is larger than the sum of two single bills.
The system tries to correct this via splitting — instead of taxing the combined income on the single scale, the law applies a divisor (1.7–2.0 depending on canton) to drag the couple back down into a lower band. But the splitting is rarely full (= 2.0); most cantons split at 1.85 or 1.9. The undercorrection is the "marriage penalty".
A worked example
Two adults in Zürich city, both age 40, no children, identical incomes of CHF 100 000 each. Combined income CHF 200 000.
- If both single (filed separately, hypothetically): ~CHF 13 400 each → CHF 26 800 total.
- If joint married, summed CHF 200 000 on the married scale: ~CHF 35 900.
- Marriage penalty: CHF 9 100 extra per year, every year.
Who pays the penalty
Not every married couple. The penalty bites hardest on:
- Dual earners with similar incomes (50–60 % vs 40–50 % split).
- High incomes (the progressivity is steepest at high incomes).
- Cantons with low splitting divisors (1.7–1.85).
Conversely, a marriage bonus exists for:
- Single-earner couples (one spouse not working — the rate-class lookup is at half-income).
- Very unequal earners (e.g. CHF 250 k + CHF 30 k).
The fix: Individualbesteuerung 2026
On 8 March 2026 Swiss voters approved Individualbesteuerung with 54.23 % Yes. After implementation (by 2032 at latest), every adult taxpayer — single or married — files their own return on their own income. The marriage penalty disappears entirely for the dual-earner archetype. The marriage bonus disappears for single-earner couples.
Many cantons are negotiating a new "partner deduction" to soften the blow for single-earner families. Exact amounts vary by canton.
What to do between now and 2032
- Don't get divorced for tax reasons. The fix is coming. The penalty over 6 years is real, but divorce-and-remarry is disproportionate.
- Consider pension contributions as a workaround. If both spouses can max their 3a (CHF 7 258 × 2 = CHF 14 516 deducted), the joint taxable income drops, and on a steep married scale the saving exceeds what two singles would save with the same contribution.
- Plan domicile timing. If you're considering relocating within Switzerland, factor in canton-specific splitting divisors. ZG (full splitting equiv.), ZH (full splitting equiv.), BS (separate scale ≡ splitting) are roughly as good as Individualbesteuerung would be. SO (1.9 splitting) and SH (1.9 splitting) are slightly worse.
- Run our couples calculator with both spouses' real numbers to see your penalty (or bonus) magnitude.