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Apple Calendar alternatives · Calendar

Open-source alternatives to Apple Calendar

Apple Calendar is not described as open source on its own site. 11 of the 75 other calendar and scheduling apps in this directory are open source, according to their own sites.

Apple Calendar is free to use. All of them are free or have a free plan.

11 tools · Listings checked up to Oct 9, 2026 · Where the facts come from

How each one differs from Apple Calendar

  1. Itsycal

    Free, tiny menu bar calendar for the Mac

    • Itsycal is free. Apple Calendar is free.
    • Only Apple Calendar lists a web app.
    • Only Apple Calendar lists an iOS app.
    • Itsycal is open source, according to its own site.
    Itsycal vs Apple CalendarItsycal pricing and details

  2. MeetingBar

    Free Mac menu bar app that shows and joins your next meeting

    • MeetingBar is free. Apple Calendar is free.
    • Only Apple Calendar lists a web app.
    • Only Apple Calendar lists an iOS app.
    • MeetingBar is open source, according to its own site.
    MeetingBar vs Apple CalendarMeetingBar pricing and details

  3. Proton Calendar

    End-to-end encrypted calendar from the maker of Proton Mail

    • Proton Calendar starts at $3.99 per month, billed every 12 months ($47.88); $4.99 billed monthly. Apple Calendar is free.
    • Only Proton Calendar lists Windows, Linux and Android apps.
    • Proton Calendar is open source and end-to-end encrypted, according to its own site.
    • Proton Calendar also covers booking links.
    Proton Calendar vs Apple CalendarProton Calendar pricing and details

  4. Merkuro Calendar

    Open-source calendar and task app from KDE for Linux

    • Merkuro Calendar is free. Apple Calendar is free.
    • Only Merkuro Calendar lists a Linux app.
    • Only Apple Calendar lists a web app.
    • Only Apple Calendar lists macOS and iOS apps.
    Merkuro Calendar pricing and details

  5. Tuta Calendar

    End-to-end encrypted calendar bundled with Tuta Mail

    • Tuta Calendar starts at €3 per month, paid yearly (€3.60 paid monthly). Apple Calendar is free.
    • Only Tuta Calendar lists Windows, Linux and Android apps.
    • Tuta Calendar is open source and end-to-end encrypted, according to its own site.
    • Apple Calendar also covers tasks and natural-language input.
    Tuta Calendar pricing and details

  6. Fossify Calendar

    Open-source Android calendar with no ads, tracking or account

    • Fossify Calendar is free. Apple Calendar is free.
    • Only Fossify Calendar lists an Android app.
    • Only Apple Calendar lists a web app.
    • Only Apple Calendar lists macOS and iOS apps.
    Fossify Calendar pricing and details

  7. Etar

    Open-source Material Design calendar for Android

    • Etar is free. Apple Calendar is free.
    • Only Etar lists an Android app.
    • Only Apple Calendar lists a web app.
    • Only Apple Calendar lists macOS and iOS apps.
    Etar pricing and details

  8. GNOME Calendar

    Free, open-source calendar app for the GNOME desktop on Linux

    • GNOME Calendar is free. Apple Calendar is free.
    • Only GNOME Calendar lists a Linux app.
    • Only Apple Calendar lists a web app.
    • Only Apple Calendar lists macOS and iOS apps.
    GNOME Calendar pricing and details

  9. Timeful

    Free, open-source group availability poll with calendar autofill

    • Timeful is free. Apple Calendar is free.
    • Only Apple Calendar lists macOS and iOS apps.
    • Timeful is open source and self-hostable, according to its own site.
    • Timeful also covers surveys.
    Timeful pricing and details

  10. Rallly

    Open-source meeting polls for finding a time that suits a group

    • Rallly starts at $6 per seat / month, billed yearly ($10 billed monthly). Apple Calendar is free.
    • Only Apple Calendar lists macOS and iOS apps.
    • Rallly is open source and self-hostable, according to its own site.
    • Apple Calendar also covers tasks, natural-language input and calendar.
    Rallly pricing and details

  11. Crab Fit

    Free, open-source availability heat map for group events

    • Crab Fit is free. Apple Calendar is free.
    • Only Crab Fit lists an Android app.
    • Only Crab Fit lists a browser extension.
    • Only Apple Calendar lists macOS and iOS apps.
    Crab Fit pricing and details

Common questions

Is there an open-source alternative to Apple Calendar?

Yes. Itsycal, MeetingBar, Proton Calendar, Merkuro Calendar, Tuta Calendar, Fossify Calendar, Etar, GNOME Calendar and 3 more are open source, according to their own sites.

Is Apple Calendar open source?

Apple Calendar is not described as open source on its own site. The listing was checked on Oct 5, 2026 against the pages it cites.

When was this checked?

Each listing shows its own date. On this page they run from Oct 5, 2026 to Oct 9, 2026. Vendors change prices and plans without notice, so confirm on their site before you buy.

This page is built from the listings. A tool is here because its listing says so, and the order is how close each is to Apple Calendar: the alternatives its listing names first, then the tools that share the most features with it.