The most common panic: an official letter in German or French, and no idea whether it is a bill, whether it is final, and whether the clock is ticking. Pick the words printed on your letter and get, in plain language: what it is, what to do, the deadline, and what ignoring it costs.
Even day one of a deadline is tricky: with A-Post Plus the clock starts at delivery, not at the date printed on the letter. The Federal Court hears such disputes regularly, so even the Swiss get this wrong.
An advance bill based on your last declaration or an estimate, not the final amount. Cantonal and municipal tax is typically split into three installments due 30 June, 30 September and 31 December; the exact schedule varies by canton and is printed on the bill.
What to do
Pay each installment by its due date. If your income changed a lot (job change, arrival mid-year), write to the tax office and ask to adjust the provisional amount instead of silently overpaying or underpaying.
Deadline
The due dates printed on the bill (typical pattern: 30.06 / 30.09 / 31.12).
If you ignore it
No fine, but late interest accrues on the unpaid part and the shortfall lands on the final bill later, all at once.
Final assessment: your 30-day window to object starts now
Definitive VeranlagungVeranlagungsverfügungEinschätzungsentscheidDécision de taxationdecision, appealablestrict deadline
What it is
The decision that fixes your taxable income and tax for the year. This is not just a bill: once it becomes legally binding, the numbers stay, right or wrong.
What to do
Compare every line against your declaration immediately: rejected deductions, wrong income, wrong tariff. If anything is off, file an Einsprache: a written, signed letter with reasons and documents, sent by registered mail. The procedure is free.
Deadline
30 days, starting the day after delivery. It cannot be extended; late objections are only heard in narrow restoration cases (serious illness, military service). Mind that with A-Post Plus the delivery date, not the letter date, starts the clock.
If you ignore it
The assessment becomes rechtskraeftig (legally binding) and you can no longer contest it. A missed deduction or an error against you is locked in; real cases run into thousands of francs.
The settlement that follows the assessment: total tax minus your provisional payments, plus or minus interest. It can arrive months after filing, sometimes for a year long past, and can be a refund as well as a demand.
What to do
Pay by the due date on the bill. Check the interest lines. If you disagree with the tax itself, that fight belongs to the assessment decision and its 30-day window, not to this bill. Cannot pay at once? Ask the tax office for installments (Ratenzahlung) in writing before the due date.
Deadline
The due date printed on the bill, typically 30 days.
If you ignore it
Default interest, then a formal reminder, then debt collection (Betreibung), which leaves a record that landlords and lenders check.
A formal reminder, either to pay an overdue bill or to file the tax return you did not submit. Usually carries a fee and a short final deadline. It is the step right before things get expensive.
What to do
Act within the stated days: pay, or file, or if you cannot pay, request installments in writing now. If it is about a return you cannot finish, ask for a deadline extension immediately; extensions are routine, ignoring is not.
Deadline
The final date stated in the letter, typically 10 to 30 days.
If you ignore it
Unpaid bill: debt collection. Unfiled return: the office assesses you at its own discretion (Ermessensveranlagung), usually not in your favor, plus a fine.
Discretionary assessment: the office guessed your income. Answer in 30 days
ErmessensveranlagungEinschätzung nach pflichtgemässem ErmessenTaxation d'officedecision, appealablestrict deadline
What it is
You did not file despite a reminder, so the office estimated your income and wealth itself, deliberately so you gain nothing by staying silent: previous years, job, family and asset development all get extrapolated upward.
What to do
Within 30 days submit the complete missing tax return with evidence; it counts as your objection (Einsprache) and lets real numbers replace the estimate. Half-measures do not work: you must prove the assessment is obviously wrong, with documents.
Deadline
30 days from the day after delivery, non-extendable.
If you ignore it
You pay the estimated amount. After the window closes it is nearly impossible to fix; documented cases end at around 20'000 CHF of extra tax that a filed return would have avoided.
SteuererklärungNOV-FormulareDéclaration d'impôtforms to fill
What it is
The invitation to file your yearly return, on paper or online. If you are taxed at source and requested (or were forced into) ordinary assessment, this is where the NOV becomes real paperwork.
What to do
File by the cantonal deadline, usually 31 March. Not ready? Request an extension online before the deadline; the first months are typically free and granted automatically. Gather pillar 3a certificates, salary statement and insurance premium statements early.
Deadline
Usually 31 March; extensions to autumn are routine in most cantons if requested in time.
If you ignore it
Reminder with a fee, then discretionary assessment plus a fine (see Ermessensveranlagung above).
Got the letter sorted? See when the next payments will actually hit your account: cash-flow timeline
General information, not tax or legal advice. Letters differ by canton; when in doubt about your specific case, contact the office named in the letter or a tax advisor before the deadline passes.