How do I file a Swiss tax return (Steuererklärung)?

Swiss tax returns are filed with your cantonal tax authority, not a federal body. Each canton has its own deadlines — typically March 31 for the prior year, though most cantons grant automatic extensions to September 30 upon request. Some cantons allow extensions until the end of the year.

The process is done digitally via your canton's tax software (e.g., ZHprivateTax for Zurich, TaxMe-Online for Geneva). You declare income from all sources, claim deductions, and submit electronically. The authority then issues an assessment (Veranlagungsverfügung) showing the final tax due.

Key deductions to claim: professional expenses (up to CHF 3,000 for employed persons as a flat rate, or actual documented costs), commuting costs, meals, Pillar 3a contributions, charitable donations, insurance premiums, and childcare. Married couples are taxed jointly, which can create a marriage penalty at higher incomes.

This is general information only, not professional tax advice. Consult a qualified tax professional for your specific situation.