Open Source Google Calendar AlternativesTop Calendar Apps like Google Calendar

Alternatives list

1. 

   

   Fossify Calendar

    68 likes

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

   72 Fossify Calendar alternatives

   Cost / License

   • Free
   • Open Source (GPL-3.0)

   Application type

   • Calendar

   Origin

   • India

   Since

   • Since 2024

   Platforms

   • Android
   • Android Tablet
   • F-Droid
   • OpenAPK

   • India

   

   

   

   More about Fossify Calendar  

   

   Good alternative?Is Fossify Calendar a good alternative to Google Calendar?

    

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   3comments

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   Fossify Calendar vs Google Calendar Comments

   Positive comment by amphetamachine · Jun 19, 2026

   Numerous outstanding bugs make Fossify Calendar not recommendable as a working alternative to Google Calendar. Some I've personally experienced: Often fails to display events in the calendar; Interprets event recurrence information incorrectly; Re-writes UIDs when importing, leading to duplicating events on re-import/update.

   Comment by bulldogs · Sep 25, 2026

   Fossify Calendar and Google Calendar are not the same kind of thing, and that decides whether the swap does what you want. Google Calendar is a service: the data, sharing, invitations and access control live on Google servers, and the Android app is one client for it. Fossify Calendar is only a client. It keeps events in a local database on the phone, and its CalDAV sync option just reads whatever calendar accounts Android already holds - which can be a Google account, or a Nextcloud, Radicale or Fastmail calendar bridged in through DAVx5. So if the problem is the Google app itself (its interface, or needing Google software on the phone at all), Fossify fixes that while still showing the same calendars. If the problem is Google holding the data, Fossify alone changes nothing; you also need a CalDAV server you control, and sharing and invitations then become whatever that server offers. Two hard limits either way: it is Android-only with no web or desktop view, and a purely local calendar has no server behind it, so nothing can be shared or invited from it at all.

   Positive comment by Guest · Oct 6, 2024

   Customizable and you have control over your data.

   3 of 3 comments

   

   

   • Fossify Calendar is Free and Open SourceGoogle Calendar is Free Personal and Proprietary
   • Fossify Calendar is Privacy focused, Customizable and LightweightGoogle Calendar is not according to our users
2. 

   

   Tuta Calendar

    52 likes

   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.

   51 Tuta Calendar alternatives

   Cost / License

   • Freemium
   • Open Source (GPL-3.0)

   Application type

   • Calendar

   Origin

   • Germany
   • EU

   Since

   • Since 2024

   Platforms

   • Online
   • Android
   • iPhone
   • Android Tablet
   • iPad
   • F-Droid
   • OpenAPK
   • Thunderbird

   • Germany
   • EU

   

   

   

   More about Tuta Calendar  

   

   Good alternative?Is Tuta Calendar a good alternative to Google Calendar?

    

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   1comment

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   Tuta Calendar vs Google Calendar Comments

   Positive comment by JOPloume · Apr 20, 2025

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

   1 of 1 comments

   

   

   • Tuta Calendar is Freemium and Open SourceGoogle Calendar is Free Personal and Proprietary
   • Tuta Calendar is Privacy focused, Lightweight and CustomizableGoogle Calendar is not according to our users
4. 

   

   Etar

    89 likes

   Material design open source calendar for Android.

   Cost / License

   • Free
   • Open Source (GPL-3.0)

   Application type

   • Calendar

   Origin

   • Germany
   • EU

   Since

   • Since 2015

   Platforms

   • Android
   • Android Tablet
   • F-Droid
   • OpenAPK

   • Germany
   • EU

   

   

   

   +8

   

   More about Etar  

   

   Good alternative?Is Etar a good alternative to Google Calendar?

    

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   5comments

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   Etar vs Google Calendar Comments

   Top Negative Comment by paddling583 · Jul 2, 2024

   It has a terrible interface and the description lied about it being a material design. It also lacks export and sync.

   Negative comment by Guest · Jan 24, 2025

   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;

   Negative comment by Third Opinion · Apr 12, 2022

   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.

   3 of 5 comments

   

   

   • Etar is Free and Open SourceGoogle Calendar is Free Personal and Proprietary
   • Etar is Lightweight and Privacy focusedGoogle Calendar is not according to our users
5. 

   

   KashCal

    14 likes

   A privacy-first calendar that works offline and looks beautiful. Connect to iCloud — or don't. Your schedule, your choice.

   58 KashCal alternatives

   Cost / License

   • Free
   • Open Source (Apache-2.0)

   Application type

   • Calendar

   Since

   • Since 2026

   Platforms

   • Android
   • F-Droid
   • OpenAPK

   

   

   

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   Good alternative?Is KashCal a good alternative to Google Calendar?

    
6. 

   

   Nextcloud Calendar

    35 likes

   Calendar interface for CalDAV enabling cross-device event sync, web-based editing, recurring events, Nextcloud Contacts integration, WebCal subscriptions, attendee invites, color coding, event notifications, privacy-focused hosting, and import/export support.

   Cost / License

   • Free
   • Open Source (AGPL-3.0)

   Application type

   • Calendar

   Origin

   • Germany
   • EU

   Since

   • Since 2018

   Platforms

   • Online
   • Self-Hosted
   • Nextcloud

   • Germany
   • EU

   

   More about Nextcloud Calendar  

   

   Good alternative?Is Nextcloud Calendar a good alternative to Google Calendar?

    

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   2comments

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   Nextcloud Calendar vs Google Calendar Comments

   Positive comment by Guest · Nov 30, 2019

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

   Comment by bulldogs · Sep 22, 2026

   The split that decides this one is which side owns the runtime that reacts to a calendar change.

   Google Calendar is scriptable from inside the account: CalendarApp in Apps Script creates and moves events and reads guest lists, an onEventUpdated trigger fires when something changes, and the advanced Calendar service exposes the full v3 API including watch channels. Nothing to host, no credentials past one authorization - and none of that surface exists outside Google.

   Nextcloud Calendar is plain CalDAV on a server you run, so any client speaks to it - Thunderbird, DAVx5, a script of your own - and the events sit in a database you can query directly. There is no in-place scripting runtime, though: reacting to a change means polling, a Flow rule, or an app you write, and you supply the host and the scheduler.

   Both speak CalDAV, so neither is a closed box. Pick by which half is hard. Automation already touching Gmail, Sheets or Drive favours the trigger that lives next to the data; own infrastructure, and events you need queryable or portable across providers, favours CalDAV.

   2 of 2 comments

   

   

   • Nextcloud Calendar is Free and Open SourceGoogle Calendar is Free Personal and Proprietary
   • Nextcloud Calendar is Privacy focusedGoogle Calendar is not according to our users
8. 

   

   Calendula

    6 likes

   A modern Material 3 Expressive calendar for Android. Reads, writes, and reminds — on top of the system calendar, with zero network access.

   Cost / License

   • Free
   • Open Source (MIT)

   Application type

   • Calendar

   Origin

   • Germany
   • EU

   Since

   • Since 2026

   Platforms

   • Android
   • Android Tablet
   • Obtainium
   • F-Droid

   • Germany
   • EU

   

   

   

   More about Calendula  

   

   Good alternative?Is Calendula a good alternative to Google Calendar?

    
9. 

   

   fruux

    37 likes

   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!

   64 fruux alternatives

   Cost / License

   • Freemium
   • Open Source

   Application type

   • Calendar

   Origin

   • Germany
   • EU

   Since

   • Since 2009

   Platforms

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

   • Germany
   • EU

   

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10. 

    

    Merkuro Calendar

     13 likes

    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.

    125 Merkuro Calendar alternatives

    Cost / License

    • Free
    • Open Source

    Application typeApplication types

    • Todo List Manager
    • Calendar

    Origin

    • Germany
    • EU

    Since

    • Since 2021

    Platforms

    • Linux
    • Flathub
    • Flatpak
    • Linux Mobile

    • Germany
    • EU

    

    

    

    +5

    

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11. 

    

    Right Calendar

     11 likes

    Right Calendar app is a versatile scheduling tool that offers unparalleled flexibility to its users. One of its standout features is that it is built on an open-source platform. This not only ensures transparency but also allows for constant updates and bug fixes from a...

    Cost / License

    • Free Personal
    • Open Source (GPL-3.0)

    Application typeApplication types

    • Calendar
    • Todo List Manager

    Origin

    • International

    Since

    • Since 2025

    Platforms

    • Android

    • Global

    

    

    

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12. 

    

    Kolab

     43 likes

    Kolab provides a FOSS communication & collaboration solution that can be completely self-hosted. Take back control of your data and access it via the webinterface, or existing mobile & desktop clients.

    Cost / License

    • Freemium
    • Open Source

    Application type

    • Calendar

    Origin

    • Switzerland

    Since

    • Since 2011

    Platforms

    • Linux
    • Online
    • Self-Hosted

    

    Good alternative?Is Kolab a good alternative to Google Calendar?

     
13. 

    

    Kontact

     37 likes

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

    Cost / License

    • Free
    • Open Source

    Application typeApplication types

    • Calendar
    • Email Client

    Origin

    • Germany
    • EU

    Since

    • Since 2010

    Platforms

    • Linux
    • Flathub

    • Germany
    • EU

    

    More about Kontact  

    

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14. 

    

    SilentSuite

     4 likes

    End-to-end encrypted sync for calendar, contacts and tasks. Integrates with your existing apps, data is encrypted on your devices before it ever reaches the server.

    13 SilentSuite alternatives

    Cost / License

    • Freemium
    • Open Source

    Application type

    • Calendar

    Origin

    • United States

    Since

    • New

    Platforms

    • Online
    • Android
    • Windows
    • Mac
    • Software as a Service (SaaS)
    • Self-Hosted
    • Docker

    • United States

    

    

    

    +9

    

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