Do I need to submit all receipts with the tax return?

No. You only need to submit a summary of income and expenses. However, you must keep all receipts for 10 years — the tax office may request them during an audit.

Can I do the tax return myself?

Yes, especially with cash-basis accounting. However, a fiduciary can optimize your deductions and often saves more taxes than they cost. From roughly CHF 80,000 profit, a fiduciary is generally worth considering.

Filling out the tax return as a sole proprietorship

How to complete your tax return as a Swiss sole proprietor — which forms you need, which attachments are required, and how to avoid common mistakes.

1 min read

Which forms do you need?

As a sole proprietor, you fill out the regular personal tax return plus an additional form for self-employment income (varies by canton). You list your business income and expenses there. The profit (income minus expenses) is added to your personal income and taxed together.

What you can deduct

All business-related expenses: materials, rent for office or workspace, telephone and internet (business share), vehicle costs (business kilometers), insurance, professional development, office supplies, depreciation on business assets, and interest on business loans. Keep receipts for everything — the tax office may ask even years later.

Common mistakes

The most common mistakes: forgetting to claim depreciation (this is free money you're leaving on the table), claiming private expenses as business expenses (the tax office flags this), not separating business and private vehicle use clearly, and — the most expensive one — missing the filing deadline and paying a penalty.

Deadlines

The filing deadline is usually March 31 of the following year (varies by canton). An extension can be requested — in most cantons, online and without justification. The extension doesn't delay the tax payment, only the filing obligation. Pay the provisional tax bill on time to avoid interest.

Accurate as of: The rates and amounts mentioned in this article reflect the state as of 7 August 2026. They are for information only and do not replace tax or legal advice. For binding information, contact the Swiss Federal Tax Administration (ESTV), your cantonal tax office, or a fiduciary.

Frequently asked questions

Do I need to submit all receipts with the tax return?: No. You only need to submit a summary of income and expenses. However, you must keep all receipts for 10 years — the tax office may request them during an audit.
Can I do the tax return myself?: Yes, especially with cash-basis accounting. However, a fiduciary can optimize your deductions and often saves more taxes than they cost. From roughly CHF 80,000 profit, a fiduciary is generally worth considering.