How can I apply for an extension of the deadline for filing a tax return in Switzerland?

Overview of Extension Options

In Switzerland, it is possible to request an extension for the tax return deadline in all cantons. Most cantons grant these extensions generously and often at no additional cost.

Basic Requirements for Extensions

Timely Application

Most Important Rule: The application must be submitted before the original deadline expires

• Too Late: After the deadline expires, it becomes more difficult and often subject to fees
• Exceptions: In special circumstances (illness, emergency), extensions may also be granted retroactively

No Justification Required

• Most cantons do not require a detailed justification
• A simple request for an extension is usually sufficient
• For repeated extensions, further inquiries may occur

Extension Deadlines by Canton

Standard Extension (First Extension)

• Zurich: until September 30 (automatic)
• Bern: until July 15 (often automatic with online submission)
• Aargau: until September 30
• Basel-Stadt: until September 30 (automatic with online submission)
• St. Gallen: until September 30
• Lucerne: until September 30

Further Extensions Possible

• Second Extension: usually until November 30
• Third Extension: until December 31 (granted less frequently)
• Special Circumstances: also possible beyond the end of the year

Deviating Cantons

• Geneva: until September 30, further until December 31
• Vaud: September 30 standard
• Ticino: until September 30, often longer
• Valais: flexible handling depending on the situation

Application Procedures by Canton

Online Procedures (Preferred)

Zurich

• Portal: "eTax Zurich"
• Procedure: Automatic extension with online registration
• Deadline: until September 30 without further application
• Costs: free of charge

Bern

• Portal: "BeTax" or AGOV (Swiss Government Login)
• Procedure: Fill out online form
• Confirmation: automatic confirmation
• Costs: free until July 15

Basel-Stadt

• Portal: "eSteuern Basel-Stadt"
• Special Feature: Automatic extension until September 30 with online use
• Further Extension: separate application required

Written Applications

Informal Letter

Simple letter with the following information:

• Full name and address
• Tax number or social security number
• Tax year
• Requested extension deadline
• Date and signature

Example Text:

Dear Sir or Madam,

I hereby request an extension of the deadline for submitting
my tax return for 2024 until September 30, 2025.

Name: [Your Name]
Address: [Your Address]
Tax Number: [if known]

Sincerely,
[Signature]


Official Forms

• Many cantons offer special forms
• Download usually available on the tax administration website
• Fill out and send by mail or email

Telephone Applications

Availability

• Smaller Cantons: often possible
• Larger Cantons: usually only in writing or online
• Personal Consultation: telephone numbers on cantonal websites

Procedure

• Have tax number and personal data ready
• State desired extension deadline
• Request written confirmation

Automatic Extensions

Cantons with Automatic Extension

Some cantons grant automatic extensions under certain conditions:

Zurich

• Automatic until September 30 with online registration
• No further action required
• Reminder via email

Basel-Stadt

• Automatic until September 30 with online use
• Only with first-time use of the online portal

Requirements for Automatic Extension

• Registration in the online portal before original deadline
• No previous defaults
• Complete profile data deposited

Costs for Extensions

Free Extensions

• First Extension: free of charge in all cantons
• Until September 30: usually without fees
• Online Applications: generally free of charge

Paid Extensions

• After September 30: partial fees
• Multiple Extensions: from the second or third extension often subject to fees
• Fees: 20-100 CHF depending on canton and situation

Fee Examples

• Bern: free until July 15, 20 CHF until September 15, 40 CHF until November 15 (online) / 60 CHF (written/telephone)
• Aargau: first reminder 35 CHF, second reminder 50 CHF
• St. Gallen: extension beyond November may be subject to fees
• Solothurn: free until July 31, 30 CHF until November 30

Special Situations

Illness or Emergencies

• Medical Certificate: for prolonged illness
• Accommodating Treatment: retroactive extensions also possible
• No Fees: for proven emergencies

Complex Tax Cases

• Self-Employed: often longer extensions possible
• International Matters: additional time for obtaining foreign documents
• Inheritance Cases: special regulations in case of death

First-Time Tax Liability

• Accommodating Treatment: for first tax returns
• Consultation Appointments: free support available
• Longer Deadlines: often possible until year-end

Extension for Tax Advisors

Professional Representatives

• Blanket Extensions: for trustees and tax advisors
• Until December 31 of the Declaration Year: often possible
• Collective Powers of Attorney: for multiple clients simultaneously

Requirements

• Professional Authorization: registered tax advisors
• Power of Attorney: written authorization required
• Early Application: usually by original deadline

Digital Tools

Reminder Services

• Email Notifications: automatic reminders
• SMS Service: available in some cantons
• App Notifications: with mobile apps from tax administrations

Online Portals Overview

• Zurich: eTax Zurich
• Bern: BeTax / AGOV
• Aargau: eSteuern Aargau
• Basel-Stadt: eSteuern Basel-Stadt
• St. Gallen: eTax St. Gallen

Avoiding Common Mistakes

Application Too Late

• Problem: Application after deadline expires
• Solution: Set calendar entries and reminders
• Emergency: immediate contact with tax administration

Incomplete Information

• Problem: missing tax number or address
• Solution: have all documents ready before applying
• Post-Processing: can lead to delays

Wrong Contact Points

• Problem: application directed to wrong authority
• Solution: check website of responsible tax administration
• Forwarding: usually automatic, but time-consuming

Practical Tips

Early Planning

• Beginning of Year: think about extension already in January
• Complex Cases: organize professional help in time
• Collect Documents: continuous documentation throughout the year

Communication with Authorities

• Polite and Precise: make clear statements
• Request Confirmation: written confirmation of extension
• Keep Contact Details Current: be reachable for inquiries

Backup Plans

• Plan B: check alternative extension options
• Professional Help: tax advisor as emergency solution
• Partial Submission: incomplete declaration as interim solution

Legal Basis

Legal Foundation

• Cantonal Tax Laws: individual regulations
• Tax Procedure Law: uniform basic principles
• Discretionary Powers: authorities have certain flexibility

Appeal Options

• Rejections: can be appealed
• Appeal Instance: cantonal tax appeal commission
• Deadlines: usually 30 days for objections

Extension vs. Early Submission

Advantages of Early Submission

• Faster Refund: for credit balances
• Less Stress: no time pressure
• Better Advice: more time for inquiries

When Extension Makes Sense

• Missing Documents: important documents not yet available
• Complex Matters: sufficient time for correct processing
• Professional Overload: process during quieter times

Conclusion

Requesting a deadline extension for the tax return in Switzerland is straightforward and usually free of charge. The key is timely application before the original deadline expires. Preferably use online procedures, as these often enable automatic extensions and are processed faster. In special circumstances, tax administrations are usually accommodating and also grant exceptional extensions.