Guide · as of September 2026
Zurich tax return deadline — and how to extend it
In the canton of Zurich, your tax return is due by 31 March of the following year — so the 2026 tax return must be filed by 31 March 2027. If you request an extension in time, the deadline can be moved to 30 November at the latest; for the 2025 tax return, that means 30 November 2026.
Key dates
Which deadline applies to which tax return?
In Switzerland you always declare the previous year. The 2025 tax return (tax period 2025) was due in 2026; the 2026 tax return is filed in 2027. The standard deadline is always 31 March — together with the securities register (Wertschriftenverzeichnis), either online via ZHprivateTax, the canton’s filing portal, or by post to the scan centre.
Right now, at the end of September 2026, two groups need to watch the calendar: the self-employed, whose automatic extension ends on 30 September, and anyone who has been granted an extension to 30 November. For the 2026 tax return, the deadline is not until 31 March 2027 — your municipality sends out the forms in January 2027.
For the basics of what an extension is, see filing extension in our glossary. This page is about the actual dates and what to do.
Checklist
What’s due when — 2026 and 2027.
In date order. Applies to individuals resident in the canton of Zurich; if your municipality has approved a different date, that date applies.
Standard deadline, 2025 tax return
Passed. If you applied for an extension before this date, your extended deadline now applies.
Deadline for the self-employed
The municipal tax office extends the deadline to this date automatically. Need longer? Apply for a further extension before it runs out.
Longest regular extension
Beyond this, extensions are granted only for credible exceptional reasons. Your 2025 return must be filed by now at the latest.
Forms for the 2026 tax return
The municipal tax office sends out the forms or login details. If nothing arrives, you have to request them yourself.
Deadline, 2026 tax return
File online via ZHprivateTax or by post to the scan centre. Any extension must be requested before this date.
Extending the deadline
How to request an extension.
Four points decide whether your extension is valid. All of them come from the Zurich Finance Directorate’s directive on the tax return procedure.
Apply to the right office
Extensions are handled by the tax office of your municipality (Gemeindesteueramt), not the cantonal tax office. ZHprivateTax is for filing the return, not for extensions. Some municipalities — Winterthur among them — offer an online form.
Before the deadline expires
Your request must arrive while the current deadline is still running — before 31 March, or before the end of an extension already granted. An expired deadline can no longer be extended.
Choose a date — 30 November at most
Requests made in time are granted up to 30 November of the year after the tax year. Anything later needs a detailed explanation of exceptional circumstances.
Don’t wait for a confirmation
A first request submitted in time counts as approved unless you receive a written decision saying otherwise. You only get a letter for late requests or for requests beyond 30 November.
Extensions in Winterthur
The City of Winterthur accepts requests through an online form (E-Fristerstreckung, in German) — available around the clock. You need the AHV number printed on your tax return and your date of birth. Requests by phone are not accepted, and written requests are no longer confirmed. An extension only applies to one year and must be requested again each year.
If you live elsewhere in the canton, the same cantonal rules apply; whether there is an online form depends on your municipality. The canton itself notes that only some municipalities offer online extensions.
Cost: what an extension costs
Neither the cantonal directive nor the City of Winterthur mentions a fee for a request submitted in time (as of September 2026). Municipalities may have their own rules — if your municipality’s website says nothing, ask. For clients who have engaged us, we handle the request.
Special cases
- Self-employed: the deadline is extended to 30 September automatically — no request needed. If you need longer, apply before 30 September for an extension up to 30 November at most.
- Living outside the canton (with property or a business in Zurich): also an automatic extension to 30 September. An extension granted by your canton of residence also applies in Zurich, provided you notify Zurich in time.
- With a tax adviser or representative: if your representative files the request, any decision usually goes to them. However, a representative being busy is expressly not a reason for an extension beyond 30 November.
- Taxed at source with a subsequent ordinary assessment: the standard deadline is also 31 March. See subsequent ordinary assessment.
Missed the deadline
What happens when the deadline passes?
An expired deadline can no longer be extended. According to the cantonal directive, the reminder procedure starts immediately after the deadline and runs in these stages:
- Informal reminder (optional): the municipal tax office may first ask you by ordinary post to file within 20 days.
- Formal reminder (Mahnung): sent by A-Post Plus with a 10-day deadline that cannot be extended. The tax office may not charge a fee for the reminder.
- Discretionary assessment: if you still don’t file, the tax office estimates your income and assets so that you are presumably not better off than if you had filed. See discretionary assessment.
- Procedural fine: anyone who fails to file despite a reminder can be fined for breaching procedural obligations. For a first offence, the directive says this is usually waived.
Once the discretionary assessment arrives, you file the missing tax return — it is then treated as a formal tax objection (Einsprache). You have 30 days from delivery. This is often where we step in: prepare the return, substantiate the objection and file it on time.
Note: an extension only postpones filing, not payment. Your provisional tax invoice is not affected.
FAQ
About the tax return deadline
When is the 2025 tax return due in the canton of Zurich?
The standard deadline was 31 March 2026. With an extension requested in time, the approved date applies — 30 November 2026 at the latest. For the self-employed, the deadline is automatically extended to 30 September 2026.
How do I extend my tax return deadline in Winterthur?
Use the City of Winterthur’s online form, entering the AHV (social security) number printed on your tax return and your date of birth. The Winterthur tax office does not accept requests by phone, and the extension has to be requested again every year.
Does an extension cost anything?
Neither the cantonal directive nor the City of Winterthur mentions a fee for a request made in time (as of September 2026). Other municipalities may have their own rules — if in doubt, ask your municipal tax office. For our clients, we request the extension as part of the engagement.
Can I extend beyond 30 November?
Only in exceptional cases. The tax office needs a specific, credible account of extraordinary circumstances. According to the cantonal directive, general reasons such as missing documents or a busy tax adviser are expressly not enough.
What happens if I miss the deadline?
You receive a formal reminder (Mahnung) with a 10-day deadline that cannot be extended. If you still don’t file, the tax office estimates your income and assets at its discretion, and a procedural fine may follow. The reminder itself is free of charge.
Does an extension also postpone paying my taxes?
No. The extension only covers filing the return. The provisional tax invoice and its due date are not affected.
Related terms
Can we help?
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Book an appointment — you don’t need any documents yet. We clarify your situation in a conversation, check every deduction and file electronically. All you do is approve.