Tax return deadlines in Zürich, and how to get more time

For employees in Canton Zürich · Updated October 2026

Three dates matter for a Zürich tax return, and which ones apply to you depends on how you are taxed. Most people only ever need the first. People taxed at source need to know the third, because it is the one date nobody can move.

31 March: the ordinary deadline

The return for tax year 2026 is due on 31 March 2027. The letter with your access code for the canton's online tool arrives in January or February, and the clock runs from the start of the year regardless of when the letter reaches you.

This date is set by the canton's directives, not by the law itself, which is why the canton can and sometimes does move it: the return for 2024 was extended canton-wide to 30 April 2025. When that happens, the new date is published and this page follows it.

Asking for more time

Extensions are granted by your commune's tax office (the Gemeindesteueramt), not by the canton, so the exact way of asking differs by commune. Two things are the same everywhere:

• A first request made before the deadline needs no reason. It counts as granted unless the commune refuses it in writing.
• The usual first step is 30 September. The ceiling that binds every commune is 30 November. Beyond that, a request is refused unless you can show extraordinary grounds, such as a long illness or a stay abroad.

You ask online, with the access code from your tax office letter, or on your commune's website. Do it before 31 March. Asking after the deadline has passed is not an extension request any more, it is a late return.

The date that does not move: 31 March for tax at source

If you are taxed at source and want a tax return at all, because you earn under CHF 120,000 and want your deductions back, your written request for the ordinary assessment must reach the tax office by 31 March of the year after the tax year. That date is written into the law itself, and dates in the law cannot be extended. Miss it and the tax withheld for that year is final. The same applies to the request for correcting a wrong tariff code.

The good news, confirmed by our Treuhänder's practice: once that request is accepted, the return itself is an ordinary return. It can be extended to September or November like anyone else's. Only the request has to be in by March.

What happens if you miss the deadline

1. A reminder from your commune with a new, short deadline and a fee.
2. If nothing arrives, the tax office assesses you by estimate. Estimates are rarely in your favour, and a fine for the late return is added.
3. You can object to the estimate within 30 days, but only together with the complete return, so you end up doing the work anyway, under worse conditions.

The year at a glance

• January to February: the salary certificate from your employer, the 3a and insurance statements, the letter with your access code.
• 31 March: the return is due, or your extension request is in. For tax at source: the request for an ordinary assessment is in.
• 30 September: the usual extended deadline.
• 30 November: the last possible date without extraordinary grounds.