Taxed at source in Switzerland? When filing a tax return gets money back (2026)

Overpaid source tax comes back through an ordinary tax return. If you work in Switzerland on a B permit, you ask your cantonal tax office for a subsequent ordinary assessment (nachträgliche ordentliche Veranlagung, NOV) by 31 March of the year after the tax year, and then you file.

Why it's worth the effort: tax at source (Quellensteuer) runs on a flat schedule that builds in standard deductions only. If yours are bigger, say pillar 3a, a pension-fund buy-in or a long commute, you've been overpaying every month. Above roughly CHF 120'000 gross a year you have to file anyway. Below that, it's your call. And the popular belief that starting a job in Q4 hands back all the source tax is usually wrong.

How tax at source actually works

If you're a foreign national living in Switzerland without a C permit, your employer takes the tax out of each pay slip and sends it on to the tax office. You never file anything. For a lot of people that's roughly the right answer.

The schedule behind it is a set menu at a fixed price, costed for the average diner. It builds in lump sums that fit most people: a flat amount for work expenses, one for insurance premiums, one for children. An ordinary tax return is the same meal a la carte. You pay for your own situation, line by line. When your situation really is average, the set menu comes close enough. When your provable deductions run above the averages in the schedule, a la carte is cheaper. That gap is money that can come back to you.

Do you have to file? The CHF 120'000 line

Two cases here, and mixing them up is where the money goes missing.

• Gross employment income above roughly CHF 120'000 a year: you have to file an ordinary tax return, the obligatory NOV. It cuts both ways: money back is possible, so is a bill.
• Gross income at or below about CHF 120'000: nothing is required of you. You can still request an ordinary assessment voluntarily, and that's where most employee refunds sit (source: ESTV and the cantonal tax offices for Zurich and Aargau).

The deadline for the voluntary request is firm: 31 March of the year following the tax year, with no extension available. For the 2026 tax year that's 31 March 2027. Let it pass and the source tax deduction for that year is final.

Worth checking: the CHF 120'000 figure and the deadline are guide values for the 2026 tax year, and your canton administers both. Your cantonal tax office can confirm the current threshold and the exact steps that apply to you.

When filing actually gets money back

Filing helps when you hold deductions the source-tax schedule doesn't already contain. It covers standard lump sums. What it can't know is what you did with your own money. The usual candidates:

• Pillar 3a contributions, up to the annual maximum (around CHF 7'258 with a pension fund, the tax-year-2025 value).
• Pension-fund (2nd pillar) buy-ins, which can be sizeable.
• A commute that costs more than the flat allowance, or actual work expenses above the standard amount.
• Childcare costs, further-education costs, debt interest, alimony and donations.

Maria's pillar 3a is worth about CHF 1'800 to her. She's single, employed in Zurich and taxed at source on a gross salary of CHF 100'000, and across the year the schedule assumes nothing beyond its standard deductions. She actually paid CHF 7'258 into pillar 3a, and that amount comes off her taxable income in an ordinary assessment. At a marginal rate of roughly 25 % that's about CHF 1'800 less tax, refunded to her because it had already been withheld. A pension-fund buy-in or a long commute on top would push the number higher.

Where you live pulls on the same calculation. The source-tax rate uses a cantonal average municipal rate, so a municipality below that average tends to give the difference back through an ordinary assessment. You can put municipal tax levels side by side in the tax comparison.

The maximum amounts, rates and marginal rates above are 2026 figures. They change every year and they differ by canton, so the number that counts is the one in your canton's guidance for your own year.

"I started my job in Q4, so I get it all back", right?

This is the belief that's usually wrong, and it lands on exactly the people who arrive mid-year.

Whether a late start means a big refund depends entirely on why you only had income in the fourth quarter, and Case B runs on a rule in Swiss law. For a part-year liability, regularly flowing income such as salary is converted to a full 12 months purely to set the rate (source: DBG Art. 40, and the cantonal guidance in Zurich and Aargau). Move to Switzerland in October on CHF 8'000 a month and your CHF 24'000 of actual income gets taxed at the rate for CHF 96'000. The source tax already applied essentially that rate. So a return won't hand back the "missing" nine months. It works only through the deductions the schedule left out.

Case A is a different animal. Live in Switzerland all year, as a student or a non-working partner, start earning in October, and your rate is set on a genuinely low annual income. A large part of what came off at the higher monthly rate can come back.

A voluntary filing is a one-way door

In most cantons the voluntary request binds the following years too, once it's made, until you get a C permit or leave Switzerland. From then on there's an ordinary return every year. In a year with smaller deductions that can cost more than the source tax would have taken. A move to a more expensive municipality tips it the same way. Going back to plain source taxation is generally off the table. So it's a calculation, not a reflex: work out roughly whether your deductions beat the schedule before you commit. If they clearly do and your situation is stable, it usually pays.

If it's close, it deserves a proper look.

What to do before 31 March

If an ordinary assessment looks like it could go your way, a short checklist:

1. Gather your salary statement (Lohnausweis), your pillar 3a certificate, any pension-fund buy-in confirmation, and receipts for commuting, further education, childcare and the like.
2. Estimate whether those deductions are meaningfully larger than the standard lump sums in the schedule.
3. If they are, request the subsequent ordinary assessment from your cantonal tax office in time, by 31 March of the following year.
4. File the ordinary tax return that follows, and have the source tax you already paid credited against it.

What you actually end up filing

The return behind an ordinary assessment is a normal Swiss tax return, nothing exotic. TaxWize reads your salary statement, your pillar 3a certificate and the rest of your documents, puts each item under the right deduction, and shows whether an ordinary assessment is likely to land below what was already withheld, for standard employed situations in the cantons it covers. Genuinely cross-border cases, with foreign income or split residence, are still worth taking to a professional. For a straightforward salary and the usual deductions, though, that arithmetic is the whole decision.