Withholding tax: when the subsequent ordinary assessment is worth it for you
Updated: · General information, not tax advice
In short: withholding tax comes off your salary with flat-rate deductions already built in. For your own deductions to actually count, you have to request the subsequent ordinary assessment by 31 March — that deadline is not extended — and the decision is final: you keep declaring in the years that follow.
If you work in Switzerland on a B permit, are a cross-border commuter, or do not have a C permit yet, your employer normally deducts the tax straight from your salary: that is withholding tax (Quellensteuer). Convenient, because you do not have to do anything. And that is exactly the problem: if you do nothing, you deduct nothing.
The rate applied to you has flat-rate average deductions baked into it. It does not know whether you pay into pillar 3a, whether you have bought into your pension fund, whether you pay for childcare or have a long commute. For any of that to count, you need the subsequent ordinary assessment — NOV for short.
1. The date everything hangs on: 31 March
The request is made by 31 March of the following year. That is not a guideline: it is a forfeiture deadline and it is not extended. Once it passes, the year stays closed at the rate that was applied — even if you would have been owed money.
It is the most expensive difference between withholding tax and ordinary assessment: there, extensions are routine; here, there are none.
2. When it is not a choice
There are cases where the tax return is not requested but owed.
- Gross employment income of CHF 120'000 or more a year. From there, ordinary assessment is compulsory.
- Assets or income that do not run through your salary. In the Canton of Zurich, CHF 80'000 in assets (CHF 160'000 for joint assessment) or CHF 3'000 in other income trigger the obligation to file. Other cantons set their own limits.
And one detail that surprises a lot of people: if you reach the CHF 120'000 in a single year, you stay under the obligation to file until your liability to withholding tax ends, even if you earn less in the years that follow.
3. What you can claim back
What the average rate does not know about, but a tax return can take in. Every canton sets its own limits and conditions:
- Contributions to pillar 3a.
- Buying in contribution years to your pension fund (2nd pillar).
- Childcare costs.
- Maintenance payments you make.
- Debt interest.
- Actual professional expenses, where they exceed the flat-rate deduction: long commutes, meals away from home, further training.
- Medical costs above the canton's threshold.
That something comes out in your favour at the end is not guaranteed: it depends on your situation, on your canton and on your municipality.
4. The catch: the decision is final
This is almost always missing from articles that only talk about "getting money back":
- The request cannot be revoked. Once it is made, the year is settled through the tax return.
- So are the years that follow. Once you are in the subsequent ordinary assessment, you keep declaring every year for as long as you are subject to withholding tax — even if the reason for the request no longer applies.
- You can end up owing more. With a high tax multiplier in your municipality, or a changed situation, the result can be worse than the deduction at source.
Which is why it is better to do the sums before the request, not after.
5. If only one detail is wrong, you may not need a return at all
If the problem is that the rate was applied wrongly — marital status, children, religious denomination, a wrongly reported level of employment — there is the tariff correction (Tarifkorrektur). It fixes the calculation without putting you under the obligation to file, and it has the same 31 March deadline. That is the simpler route if your situation is otherwise normal.
6. How we help
We prepare your tax return from your documents, or we check the one you have already done, line by line against your receipts, with a second independent AI check and a sealed verification log you can show later. Fixed price CHF 49. Today we work the Canton of Zurich.
The first result is free: you learn how many line items add up and how many need attention, before you pay anything. If your case is genuinely complex, we tell you beforehand — then a qualified professional is the better choice.
Which documents you need for it is in the checklist; the deadlines for the ordinary return — and why they do not apply here — in deadline and extension.
See how it works and get started →
7. Frequently asked questions
By when can I request the subsequent ordinary assessment?
By 31 March of the year following the tax year. That is a forfeiture deadline and it is not extended: after that day the year is closed at the withholding tax rate that was applied to you.
Will the request definitely get me money back?
No. It depends on your actual deductions, on your canton and on your municipality's tax multiplier. It can come out in your favour, come out at zero, or leave you owing more. That is why it is better to do the sums before the request, not after.
Can I withdraw the request?
No. The request cannot be revoked, and once you are in the subsequent ordinary assessment you file a tax return every year for as long as you are subject to withholding tax — even if the reason for the request no longer applies.
What is the difference from a tariff correction?
A tariff correction fixes a detail that was applied wrongly in the rate (marital status, children, religious denomination, level of employment), without putting you under the obligation to file a return. It has the same 31 March deadline and is the simpler route if your situation is otherwise normal.
8. Notice
This page is general information about withholding tax and the subsequent ordinary assessment, and does not constitute tax or legal advice. The thresholds and deductions mentioned depend on your canton and your municipality, and other cantons have their own rules; the figures given for assets and other income are those of the Canton of Zurich. You file the return yourself.