The Best Open Source Google Calendar AlternativesTop Calendar Apps like Google Calendar

The best open source alternative to Google Calendar is Etar. 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, Fossify Calendar, Tuta Calendar and Nextcloud Calendar.

filter to find the best alternatives

Google Calendar alternatives are mainly Calendar Apps, but if you're looking for Todo List Managers or Email Clients you can filter on that. Other popular filters include Android + Open Source and Windows + Open Source. You can also filter by region, for example EU-based alternatives if you prefer software developed in the European Union. These are just examples - use the filter bar below to find more specific alternatives to Google Calendar.
Google Calendar iconGoogle Calendar
  936
  • ...

Manage events efficiently with device syncing, Gmail integration, event reminders, and shareable schedules on a user-friendly interface with dark mode.

More about Google Calendar
More about Google Calendar
Google Calendar alternatives page was last updated Apr 20, 2025
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  1. Etar icon

    Etar

     79 likes
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    Material design open source calendar for Android.

    49 Etar alternatives

    License model

    • Free • Open Source

    Application type

    Country of Origin

    • DE flagGermany
    • European Union flagEU

    Platforms

    • Android
    • Android Tablet
    • F-Droid
    Etar screenshot 1

    Properties

    1.  Lightweight
    2.  Privacy focused

    Features

    1.  Material design
    2.  Ad-free
    3.  No Tracking
    4.  Works Offline
    5.  Dark Mode
    6.  Multiple Account support
    7.  GPS Location Tracking

    Etar VS Google Calendar

     
    Comments about Etar as an Alternative to Google Calendar
    Top Positive Comment
    Guest
    Nov 23, 2019
    6

    Nice, clean, and to the point calendar!

    Top Negative Comment
    Third Opinion
    Apr 12, 2022
    2

    Import and export function is listed but it didnt work for me at all. Worse, on my latest phone I could not even import an ICS file with all my stuff.

    Most Recent Comment
    Guest
    Negative Jan 24, 2025
    0

    does not conform to UNIX principles (let the application be one, but it will work well and cooperate with other functions and applications in the system); The interface is hideous. Nothing is anywhere, it's hard to figure out; It is not practical. Notion Calendar or Apple Calendar for example have a lot of common handy features that Etar doesn't have;

    Show more comments
    3 of 5 comments
    Google Calendar Icon
    Etar icon

    • Almost everyone thinks Etar is a great Google Calendar alternative.

    • Etar is the most popular Android & Android Tablet alternative to Google Calendar.

    • Etar is the most popular Open Source & free alternative to Google Calendar.

    • Etar is Free and Open SourceGoogle Calendar is Free and Proprietary
    • Etar is Lightweight and Privacy focusedGoogle Calendar is not according to our users
  2. Calendar Lock PEA icon

    Calendar Lock PEA

     16 likes
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    Calendar encryption: View calendars and stores them encrypted on your device or in the cloud.

    67 Calendar Lock PEA alternatives

    License model

    • Free • Open Source

    Application type

    Platforms

    • Mac
    • Windows
    • Linux
    week view

    Properties

    1.  Privacy focused

    Features

    1.  Password encryption
    2.  Authenticated encryption
    3.  Encrypted Notes

    Calendar Lock PEA VS Google Calendar

     

    • Almost everyone thinks Calendar Lock PEA is a great Google Calendar alternative.

    • Calendar Lock PEA is the most popular Windows, Mac & Linux alternative to Google Calendar.

    • Calendar Lock PEA is Free and Open SourceGoogle Calendar is Free and Proprietary
    • Calendar Lock PEA is Privacy focusedGoogle Calendar is not according to our users
  4. Fossify Calendar icon

    Fossify Calendar

     33 likes
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    Your privacy-aware, open-source calendar with intuitive design and multi-platform syncing.

    49 Fossify Calendar alternatives

    License model

    • Free • Open Source

    Application type

    Country of Origin

    • IN flagIndia

    Platforms

    • Android
    • Android Tablet
    • F-Droid
    Fossify Calendar screenshot 1
    Fossify Calendar screenshot 2
    Fossify Calendar screenshot 3

    Properties

    1.  Privacy focused
    2.  Lightweight
    3.  Customizable
    4.  Support for Themes

    Features

    1.  No Tracking
    2.  Ad-free
    3.  No registration required
    4.  Works Offline
    5.  Calendar View
    6.  Dark Mode
    7.  Reminders
    8. Google Calendar icon  Sync with Google Calendar
    9.  Multiple Account support
    10.  Calendar Integration
    11.  Material design
    12. Nextcloud icon  Sync with Nextcloud

    Fossify Calendar VS Google Calendar

     
    Comments about Fossify Calendar as an Alternative to Google Calendar
    Guest
    Positive Oct 6, 2024
    0

    Customizable and you have control over your data.

    Google Calendar Icon
    Fossify Calendar icon

    • Almost everyone thinks Fossify Calendar is a great Google Calendar alternative.

    • Fossify Calendar is Free and Open SourceGoogle Calendar is Free and Proprietary
    • Fossify Calendar is Privacy focused and LightweightGoogle Calendar is not according to our users
  5. Tuta Calendar icon

    Tuta Calendar

     28 likes
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    Tuta Calendar offers secure event organization with end-to-end encryption and no ads or tracking. Enjoy multi-device sync, multiple calendar views, and offline access. Fully compliant with strict German data protection laws. Manage recurring events, unlimited calendars, and seamlessly integrate with Tuta Mail.

    30 Tuta Calendar alternatives

    License model

    • Freemium • Open Source

    Application type

    Country of Origin

    • DE flagGermany
    • European Union flagEU

    Platforms

    • Online
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • F-Droid
    Tuta Calendar screenshot 1

    Properties

    1.  Privacy focused
    2.  Customizable

    Features

    1.  Ad-free
    2.  Dark Mode
    3.  Encrypted calendar
    4.  No Tracking
    5.  Calendar View
    6.  Two-factor Authentication
    7.  End-to-End Encryption
    8.  Pomodoro Timer
    9.  Auto Responder
    10.  Cloud Sync
    11.  Reminders
    12. Google Calendar icon  Sync with Google Calendar

    Tuta Calendar VS Google Calendar

     
    Comments about Tuta Calendar as an Alternative to Google Calendar
    JOPloume
    Positive Apr 20, 2025
    0

    End-to-end encryption and works across all platforms: for me, on Android, Mac, and Windows (and even via Browser)!

    Google Calendar Icon
    Tuta Calendar icon

    • Tuta Calendar is the most popular iPad alternative to Google Calendar.

    • Tuta Calendar is Freemium and Open SourceGoogle Calendar is Free and Proprietary
    • Tuta Calendar is Privacy focusedGoogle Calendar is not according to our users
  6. Nextcloud Calendar icon

    Nextcloud Calendar

     26 likes
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    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.

    31 Nextcloud Calendar alternatives

    License model

    • Free • Open Source

    Application type

    Country of Origin

    • DE flagGermany
    • European Union flagEU

    Platforms

    • Online
    • Self-Hosted
    • Nextcloud
    Nextcloud Calendar screenshot 1

    Properties

    1.  Privacy focused

    Features

    1.  Cloud Sync
    2. Nextcloud icon  Nextcloud integration
    3.  No Tracking
    4.  Calendar View
    5.  Calendar Integration
    6.  Full-Text Search
    7.  Reminders
    8.  Dark Mode
    9.  Subtasks
    10.  Support for @mentions
    11.  Two-factor Authentication
    12.  Ad-free

    Nextcloud Calendar VS Google Calendar

     
    Comments about Nextcloud Calendar as an Alternative to Google Calendar
    Guest
    Positive Nov 30, 2019
    3

    Free (and open source) alternative. Your data is yours !

    Google Calendar Icon
    Nextcloud Calendar icon

    • Almost everyone thinks Nextcloud Calendar is a great Google Calendar alternative.

    • Nextcloud Calendar is the most popular Self-Hosted alternative to Google Calendar.

    • Nextcloud Calendar is Free and Open SourceGoogle Calendar is Free and Proprietary
    • Nextcloud Calendar is Privacy focusedGoogle Calendar is not according to our users
  7. fruux icon

    fruux

     33 likes
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    fruux is a free service that takes care of your contacts, calendars and more so you don't have to. Never manually copy contacts and calenders between your devices again!

    54 fruux alternatives

    License model

    • Freemium • Open Source

    Application type

    Country of Origin

    • DE flagGermany
    • European Union flagEU

    Platforms

    • Mac
    • Windows
    • Linux
    • Online
    • Android
    • iPhone
    • Blackberry
    • Windows Phone
    • iPad
    • Blackberry 10
    • Sailfish OS
    • Software as a Service (SaaS)
    fruux screenshot 1

    fruux Features

    1.  CardDAV Support
    2.  Contacts
    3.  CalDAV Support
    4.  Sync Contacts
    5.  Calendar Sync
    6.  CalDAV Server

    fruux VS Google Calendar

     

    • Most users think fruux is a great Google Calendar alternative.

    • fruux is the most popular SaaS alternative to Google Calendar.

    • fruux is Freemium and Open SourceGoogle Calendar is Free and Proprietary
  9. Kontact icon

    Kontact

     37 likes
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    Personal Information Manager (Mail, Contact, Calendar and more).

    109 Kontact alternatives

    License model

    • Free • Open Source

    Application types

    Country of Origin

    • DE flagGermany
    • European Union flagEU

    Platforms

    • Linux
    • Flathub
    Kontact screenshot 1

    Kontact Features

    1.  Google integration
    2.  Convert Email to Task
    3.  KDE
    4.  Feed Reader
    5.  Personal Information Manager (PIM)
    6.  Contacts

    Kontact VS Google Calendar

     
  10. Kolab Community icon

    Kolab Community

     41 likes
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    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.

    47 Kolab Community alternatives

    License model

    • Freemium • Open Source

    Application types

    Country of Origin

    • CH flagSwitzerland

    Platforms

    • Linux
    • Online
    • Self-Hosted

    Kolab Community Features

    1.  Real time collaboration
    2.  Video Conferencing
    3.  Contacts
    4.  Voice Chat
    5.  CardDAV Support
    6.  IMAP Support
    7.  CalDAV Support
    8.  WebDAV Support

    Kolab Community VS Google Calendar

     
  11. Merkuro Calendar icon

    Merkuro Calendar

     8 likes
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    Merkuro is a calendar and contact application that allows you to manage your tasks, events and contacts. Merkuro supports both local calendars as well as a multitude of online calendars: Nextcloud, Google® Calendar, Outlook®, Caldav, and many more.

    License model

    • Free • Open Source

    Application types

    Country of Origin

    • DE flagGermany
    • European Union flagEU

    Platforms

    • Linux
    Merkuro Calendar screenshot 1

    Properties

    1.  Privacy focused

    Features

    1. Google Calendar icon  Sync with Google Calendar
    2.  Calendar Integration
    3.  No Tracking
    4.  No registration required
    5.  Dark Mode
    6.  Ad-free
    7.  Recurring Tasks
    8.  Reminders
    9. KDE Plasma icon  KDE Plasma integration
    10.  KDE
    11.  Calendar Sync

    Merkuro Calendar VS Google Calendar

     
9 of 26 Google Calendar alternatives