Open Source Google Calendar Alternatives

    The best open source alternative to Google Calendar is Etar, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 100 alternatives to Google Calendar and many of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Google Calendar are Calendar Lock PEA (Free, Open Source), Lightning Calendar (Free, Open Source), Simple Calendar (Freemium, Open Source) and Nextcloud Calendar (Free, Open Source).

    This page was last updated Sep 15, 2021

    1. Why? I wanted a simple, material design, state of the art open source calendar that anyone can improve on. Features: - Month view. - Week, day & agenda view. - Uses Android calendar sync. Works with Google Calendar, Exchange, Etesync etc.
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      Etar vs Google Calendar opinions
      Almost everyone thinks Etar is a great alternative to Google Calendar.
      Nice, clean, and to the point calendar!
      Positive comment almost 2 years ago

      Open source and works well !!
      Positive comment over 3 years ago

    2. Password Encrypted Calendar: Calendar Lock PEA - Displays iCalendars that are plaintext only in RAM, but otherwise always encrypted on the device. - Uses autheticated encryption and a memory-hard key derivation function for the password.
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      Almost everyone thinks Calendar Lock PEA is a great alternative to Google Calendar.

    3. Organize your schedule and life’s important events in a calendar that’s fully integrated with your Thunderbird or Seamonkey email. Manage multiple calendars, create your daily to do list, invite friends to events, and subscribe to public calendars.
      Most users think Lightning Calendar is a great alternative to Google Calendar.
    4. A simple calendar with optional CalDAV synchronization. You can easily create recurring events and setup reminders, it can also display week numbers.
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      Simple Calendar vs Google Calendar opinions
      Almost everyone thinks Simple Calendar is a great alternative to Google Calendar.
      Open source, has widgets and is quite configurable
      Positive comment almost 3 years ago

    5. The Calendar app is a user interface for Nextcloud's CalDAV server. Easily sync events from various devices with your Nextcloud and edit them online.
      Nextcloud Calendar vs Google Calendar opinions
      Most users think Nextcloud Calendar is a great alternative to Google Calendar.
      Free (and open source) alternative. Your data is yours !
      Positive comment almost 2 years ago


    6. Kontact is the integrated Personal Information Manager of KDE. Kontact suite unites mature and proven KDE PIM applications under one roof. Thanks to the powerful KPart technology, existing applications are seamlessly integrated into one.
    7. It provides management of events and tasks, alarm notification, web export, network transparent handling of data, group scheduling, import and export of calendar files and more.
    8. GNOME Calendar is a simple and beautiful calendar application designed to perfectly fit the GNOME desktop. By reusing the components which the GNOME desktop is build on, Calendar nicely integrates with the GNOME ecosystem.
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      • FreemiumOpen Source
      • Mac
      • Windows
      • Linux
      • Online
      • Android
      • iPhone
      • Android Tablet
      • iPad
      woelkli is a service that provides secure cloud storage hosted in Switzerland. Save, view, edit and share your files from anywhere in the world, from any device
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      Woelkli vs Google Calendar opinions
      This alternative is disputed. Woelkli is still a legitimate alternative to Google Calendar, but it might have issues that some users think are important.
      It's a cloud storage service...
      Negative comment about 4 years ago

    9. Kolab is entirely Free and Open Source Software (a.k.a. FOSS), and uses Open Standards. We’ll get to why this is important to us, and hope that it is important to you thereafter.
      No screenshots yet
      Some users think Kolab Community is a great alternative to Google Calendar, some don't.
    Showing 10 of 23 alternatives