Tax Return in Switzerland: Who Must File and By When?

The annual tax return is mandatory for most people living in Switzerland. It forms the basis for calculating income and wealth taxes at federal, cantonal and municipal level. But who must file a tax return, what exceptions exist and what are the deadlines?

In this article, you will learn everything about filing obligations, deadlines and extension options.

Who must file a tax return in Switzerland?

Basic principle of tax liability

All persons tax-resident in Switzerland are required to file an annual tax return. You are liable for tax if you:

• have your domicile in Switzerland or
• spend at least 30 days with gainful employment or 90 days without gainful employment in Switzerland.

Income and assets

The tax return covers:

• Income (salary, self-employment, capital gains, pensions, etc.)
• Assets (bank balances, property, securities, cryptocurrencies, vehicles, etc.)

Married couples and registered partnerships

Married couples and registered partners file a joint tax return. Income and assets are combined and assessed together.

Minors, students and apprentices

Minors generally do not need to file their own tax return – their income and assets are attributed to their parents. Exception: earned income of minors is attributed to them personally. Adult students and apprentices must file their own tax return if they have taxable income or assets.

Special cases: When is no tax return needed?

Source-taxed persons

Foreign employees without a C settlement permit often pay withholding tax (Quellensteuer), which is deducted directly from their salary. This particularly affects persons with B or L permits and cross-border commuters.

• Generally, no tax return is required in this case.
• However, from a gross annual income of CHF 120,000, a subsequent ordinary assessment (NOV) becomes mandatory – meaning a full tax return must be filed.
• A mandatory NOV also applies with assets over CHF 80,000 (individuals) or CHF 160,000 (married couples) or with non-source-taxed income over CHF 3,000.
• Below these thresholds, source-taxed persons can voluntarily apply for a NOV by 31 March of the following year to claim additional deductions (e.g. Pillar 3a, professional expenses, pension fund purchases).

Non-employed persons with low income

In some cantons, persons without significant income or assets do not need to file a tax return. The tax authorities will inform them in writing in such cases.

Tax return deadlines

Regular deadlines

The tax return must be submitted in most cantons by 31 March of the following year. This means: for the 2025 tax year, the deadline is generally 31 March 2026.

Differences between cantons

• Zurich: 31 March
• Bern: 15 March
• Geneva: 31 March
• Vaud: 28 February (also 15 March depending on municipality)
• Valais: 31 March
• Ticino: 30 April
• Basel-Stadt: 31 March

Exact deadlines vary by canton – check the deadline on your cantonal tax office’s website.

Extension options

Requesting an extension

If you cannot submit your tax return on time, you should request an extension. In most cantons, this is free and can be done easily online. Typically, an initial extension until September is granted. A second extension until November is possible in many cantons upon request, sometimes for a fee.

Consequences of late submission

• Reminder from the tax office (in many cantons with a fee, e.g. CHF 35–60)
• Fines for repeated non-submission (up to CHF 10,000 possible)
• In the worst case, a discretionary assessment by the tax authorities – this often results in a higher tax burden than a self-filed return

Practical examples

Example 1: Employee domiciled in Zurich

An employee in Zurich must submit their tax return by 31 March at the latest. As they need more time, they request an online extension until the end of September.

Example 2: Source-taxed expat

An employee with a B permit pays withholding tax. Since she has an annual income of CHF 140,000, she is automatically subject to subsequent ordinary assessment and must file a full tax return.

Example 3: Source-taxed person under CHF 120,000

An employee with a B permit earns CHF 85,000 per year. He voluntarily applies for a NOV by 31 March to claim his Pillar 3a contributions and actual professional expenses. Thanks to the additional deductions, he receives a refund.

Common mistakes and tips

Common mistakes

• Missing the deadline and risking reminder fees
• Assuming that no tax return is needed with low income
• Confusing withholding tax with complete exemption from filing
• Missing the NOV application deadline (31 March) – this deadline cannot be extended

Tips

• Mark the submission deadline in your calendar
• Request an extension early and before the deadline expires
• Contact the cantonal tax office directly if unsure
• Gather all documents before the deadline begins
• Source-taxed persons should check whether a voluntary NOV is financially advantageous (e.g. with Pillar 3a, pension fund purchases, high professional expenses)

Conclusion

The tax return is mandatory for most people in Switzerland. Those who observe deadlines, prepare their documents on time and request an extension if in doubt avoid unnecessary reminder fees or fines. Even in special cases like withholding tax, it is worth taking a closer look: the voluntary subsequent ordinary assessment can lead to significant tax savings.