How to import a calendar to Proton Calendar

Congratulations on using the internet’s most private calendar! Now you can bring your plans and events to Proton Calendar with the help of this step-by-step guide.

Before importing your calendar

To import a calendar to Proton, first export it from a different calendar service with the file extension .ics. To find out more about how to export your calendar, check your current service FAQs. For Google Calendar export, please follow these steps. If you are an Outlook user, check these guidelines

If you want to add the imported events to a new Proton calendar, please create a calendar before importing the events.

Please note that you can import a maximum of 15,000 events at a time to Proton Calendar. If your calendar contains more than this, you can divide your file into smaller ones before importing.

Importing from a local file

1) Log in to your ProtonMail account at and switch to the Calendar app.

2) Go to Proton Calendar Settings and select Calendar from the sidebar. Then, select Import.

3) Select the .ics file from your computer and the Proton calendar where you want to import the events. Please note that the file needs to have a maximum size of 10 MB. Click on Import.

ProtonCalendar Import

4) If the file size or format is incorrect, you will get an error message. 

ProtonCalendar Import

5) Please note that certain events, calendar details, and calendar formats are currently not supported by Proton Calendar. Items that might not be imported are: 

  • Format of calendars other than Gregorian, such as Arabic, Hebrew or Chinese calendars
  • Calendar elements like To-dos, Tasks, and Journals
  • Events outside the supported date bounds. Proton Calendar currently supports events between 1970 and 2037.
  • Events based on recurrence rules that are not supported by Proton Calendar
  • Event participants
  • Email notifications

If you are trying to import any of these items, ProtonCalendar will inform you how many can be imported. If you get this notification and would still like to proceed, click on Import to start adding the events to the selected calendar. 

ProtonCalendar Import Error

6) Proton Calendar will encrypt your events and add them to the selected calendar. This might take some minutes. Do not stop this process before it is complete to avoid a partial import of your calendar.

ProtonCalendar Import

7) Proton Calendar will let you know when it has finished importing the events. Click on Close and go to your calendar to start interacting with your freshly imported events.

Please note that importing the same events twice will overwrite the existing events.