Withholding tax (Quellensteuer) for expats in Switzerland
On a B permit, your tax is deducted straight from your salary. Simple - but it can mean overpaying. Filing an ordinary return (NOV) to claim deductions like pillar 3a often triggers a refund. Here's how it works, and whether you should file.
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How withholding tax works
If you're a foreign national without a C permit, your employer deducts tax directly from your salary each month at a rate set by your canton.
This Quellensteuer covers federal, cantonal and communal tax in one single monthly deduction - you don't receive three separate bills, and there's nothing extra to pay at year-end in most cases.
The rate depends on your income level, your marital status, how many children you have, and whether you're a church member. Cantons publish their own tariffs; your employer applies the one that matches your situation and sends the tax to the canton on your behalf.
By default, you don't file a return. The withheld amount is meant to approximate your final tax - but because the tariff is a broad average, it rarely captures your personal deductions. That's why so many people at source end up overpaying quietly.
When you must file anyway (mandatory NOV)
Once your gross income passes about CHF 120,000, you're moved to ordinary assessment and must file a full return.
This is the mandatory NOV (Nachträgliche ordentliche Veranlagung). Cross the threshold in a given year and the tax office switches you from pure source tax to full annual filing - the tax already withheld is treated as an advance payment against the assessed amount.
You also file mandatorily if you have other income the source tariff can't see - self-employment earnings, rental income, or investment income above cantonal limits - or significant wealth. Getting a C permit or marrying a Swiss/C-permit spouse also moves you out of the source-tax system.
Once you're in ordinary assessment, you generally stay in it for future years, even if your income drops back below the threshold. For the full filing playbook see tax return & ordinary assessment.
When you can choose to file (voluntary NOV)
You can request ordinary assessment to claim deductions that source tax doesn't fully reflect - which often produces a refund.
Even below the CHF 120,000 threshold, you can opt in to file a full return. Claimable items include pillar 3a contributions, pension-fund buy-ins, childcare, further education, a long commute, and debt interest - none of which the flat source tariff really captures.
The request has a hard deadline: normally 31 March of the year after the tax year. Miss it and you generally can't recover that year's deductions through NOV.
The catch: opting in is largely irreversible. You commit to filing every year afterwards, including years where the maths would have been less favourable. That's not a reason to avoid it - it's a reason to model it first.
Should you file? Weighing it up
Filing pays off when your deductions clearly exceed what the source-tax rate already assumes.
The case for filing is strong if you max your pillar 3a, made a pension-fund buy-in, pay significant childcare, commute far, or have big debt interest. A refund of several thousand francs is common in those situations.
The case is weaker if you have few deductions, no 3a, no buy-in, a short commute and no children - because the source tariff already reflects a baseline of typical costs.
Because opting in is a multi-year commitment, it's worth having the whole picture modelled - which we do for you as part of a fixed-price engagement. See tax optimisation for the levers, and pillar 3a for the single biggest one.
Should you file a return (NOV)?
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Indicative, as of 2025.
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OpenWithholding tax - your questions, answered
What is withholding tax (Quellensteuer)?
It's tax deducted directly from your salary by your employer, applied to foreign nationals without a C permit. It rolls federal, cantonal and communal tax into one monthly deduction based on your income and family situation.
Do I need to file a tax return if I'm taxed at source?
Not by default. But you must file an ordinary return if your gross income exceeds about CHF 120,000, or if you have other income or significant wealth - and you can choose to file to claim deductions.
What is ordinary assessment (NOV)?
It's filing a full tax return instead of relying solely on the source-tax deduction. It lets you claim deductions the flat source-tax rate doesn't fully capture.
Can I get a refund by filing?
Often, yes. If you have deductions like pillar 3a, buy-ins, childcare or a long commute, filing an ordinary return can recover tax the source deduction overcharged.
Is opting into ordinary assessment permanent?
Largely, yes. Once you request voluntary ordinary assessment, you generally have to keep filing in future years - so it's worth checking the maths before you commit.
What's the deadline to request ordinary assessment?
Usually 31 March of the year after the tax year. Miss it and you typically can't claim that year's deductions, so it pays to decide early.
Taxed at source? You might be owed a refund
Run the checker, then let an independent expat-focused team model whether filing an ordinary return actually wins for you - before the 31 March deadline.