Subsequent ordinary taxation, explained in full

If you work in Switzerland on a B permit, your employer deducts the tax directly from your salary. That deduction follows a cantonal tariff calculated for an average situation: it knows neither your actual expenses, nor your pillar 3a, nor the cost of your childcare.

Subsequent ordinary taxation — TOU in French, NOV in German — takes you out of that flat rate. You complete a tax return like any other taxpayer, you claim your actual deductions, and the administration recalculates what you really owed. Any overpayment is refunded; any shortfall is claimed from you.

Three ways in, not to be confused

The TOU is not a single procedure. The regime depends on your domicile and your income, and the consequences are not the same.

TOU or recalculation: they are not the same thing

There is a second, lighter procedure often confused with the TOU: the request for recalculation of the withholding tax. Both are filed by the same date, but they do not open the same rights.

In other words: if your employer applied the wrong tariff — an unreported child, an outdated civil status — a recalculation is enough and has no lasting consequence. If you want to claim deductions, you need the TOU.

The deadline: 31 March, no exception

The request must reach the cantonal administration by 31 March of the year following the tax period concerned. For 2026 income, the request can therefore be filed until 31 March 2027.

This is a forfeiture deadline, not an administrative one: it is not extended, cannot be made up, and no ordinary circumstance reopens it. Once the date has passed, the year is definitively closed.

The decision is irreversible

This is the point most explanations pass over in silence, and it is the most important on this page.

That second effect deserves a pause. You do not choose year by year: you switch regime. If your situation changes — a move to a municipality with a higher rate, the end of a childcare contract, a loan repayment coming to an end — you will remain under ordinary taxation with deductions that have become smaller.

The TOU remains advantageous in the great majority of cases where the calculation recommends it. But it is decided on a trajectory, not on a single year.

What happens, step by step

1. 01

   You estimate the gain

   With your salary certificate and your actual expenses. If the estimate is negative, there is nothing to do: withholding at source is more favourable to you.

2. 02

   You file the request

   A cantonal form, to be sent before 31 March. Some cantons accept it online, others require a signed submission by post.

3. 03

   The canton confirms

   Allow four to eight weeks. You then receive the access codes for the ordinary tax return.

4. 04

   You complete the tax return

   This is the step that takes work: all income, all assets, all deductions, with supporting documents.

5. 05

   The assessment decision arrives

   The delay varies greatly by canton and period — from a few months to more than a year. The withholding tax already paid is credited, and the balance is refunded to you.

When the TOU loses you money

The withholding tariff already builds in flat rates. If your actual deductions stay below them, ordinary taxation will cost you more than the deduction at source. The profiles concerned come up often:

• Single, no children, no pillar 3a, living close to work: actual expenses are close to the flat rate, there is nothing to recover.
• A person with significant taxable wealth: wealth tax, absent from withholding at source, appears with ordinary taxation.
• A person receiving foreign income: it enters into the calculation of the rate, even when it is not taxable in Switzerland.
• A resident of a municipality with a high multiplier, whose withholding tariff was calculated on a gentler cantonal average.

Frequently asked questions