Tax instalments and filing deadlines

One of the most common surprises for those arriving in Switzerland is that tax is paid before the assessment is final. The system works on instalments: the tax authority estimates how much you will owe and asks for payments during the year, then reconciles once the return has been verified. It is a simple mechanism, but it needs to be understood — because between cantonal deadlines, interest and corporate liquidity, mistakes are costly.

Why instalments are paid

Federal, cantonal and communal tax is not calculated on a final basis until after you have filed the return and the authority has examined it. In the meantime, however, the state collects: it issues provisional statements based on the last known assessment or on an estimate of yours. These instalments anticipate the actual burden and are then compared with the real tax in the final assessment.

The principle is “pay during the year to which it relates, adjust afterwards”. Those who reason as if the tax were paid entirely the following year end up out of step with their cash flow.

Who decides the amounts

Instalments are generally based on the latest available figure: the previous year’s tax or the last final assessment. If your situation changes significantly — sharply rising or falling income, a very different corporate profit — you have two options:

Accept the proposed instalment and settle everything at the reconciliation.
Request an adjustment: notify the authority of an updated estimate, so that the instalments reflect reality. Useful in both directions: it avoids paying too much in advance or ending up with a heavy balance.

For companies, this dialogue is particularly useful in years of sharp variation in profit.

Deadlines: watch out for the canton

Here the golden rule is: there is no single Swiss deadline. Direct federal tax has a national reference deadline, but cantonal and communal taxes follow calendars set by each canton. Some provide for multiple instalments during the year, others a single deadline with the option to pay in instalments. The dates, the number of instalments and the arrangements change from one canton to another.

The practical consequence: always check your canton’s calendar and do not carry over habits picked up elsewhere. A company with offices or shareholders in different cantons must manage separate schedules.

Interest: the often-ignored lever

The Swiss system uses interest as a signal, in both directions:

If you pay early or pay more than due, many cantons grant interest in your favour (remunerative interest).
If you pay late or pay less than due relative to the final assessment, late-payment interest accrues at your expense.

The rates are set annually and vary by canton. In a liquidity context, this changes the calculation: sometimes it is worth paying early for the credit interest, sometimes it is preferable to hold onto cash. The decision must be made with the figures of the relevant canton, not out of habit.

Liquidity management

For a business, instalments are above all a matter of cash planning:

Accrue on a matching basis: set aside the tax as the profit accrues, not when the bill arrives.
Align the instalments with the collection cycle where the canton allows it.
Update the estimate during the year if the profit diverges sharply from the forecast.
Do not treat the VAT balance and the tax instalments as the same flow: they are distinct obligations, with their own deadlines and logic.

A well-managed tax budget avoids both year-end cash gaps and interest charges.

Typical mistakes

Ignoring the cantonal deadlines because they differ from the federal ones.
Not adjusting the instalments after a significant change in income or profit.
Forgetting the interest, both in your favour and at your expense.
Confusing provisional and final: the instalment is an estimate, the reconciliation comes later.

In summary

Instalments anticipate the tax before the final assessment.
They are based on the latest known figure, but you can request an adjustment.
The deadlines are cantonal: they must be checked territory by territory.
Interest works in both directions and affects cash decisions.

How we help you

We build your tax schedule to measure, adjust the instalments when your situation changes and plan liquidity so that taxes never become a surprise. Put your deadlines in order.