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aCalendar alternatives · Calendar

Open-source alternatives to aCalendar

aCalendar 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.

aCalendar has a free plan. Paid plans start at $2.49 to $11.99 per one-time in-app upgrade; aCalendar+ is $11.99. 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 aCalendar

  1. Etar

    Open-source Material Design calendar for Android

    • Etar is free. aCalendar starts at $2.49 to $11.99 per one-time in-app upgrade; aCalendar+ is $11.99.
    • Etar is open source, according to its own site.
    • aCalendar can be bought with a one-time purchase.
    • aCalendar also covers tasks.
    Etar vs aCalendarEtar pricing and details

  2. Fossify Calendar

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

    • Fossify Calendar is free. aCalendar starts at $2.49 to $11.99 per one-time in-app upgrade; aCalendar+ is $11.99.
    • Fossify Calendar is open source, according to its own site.
    • aCalendar can be bought with a one-time purchase.
    • aCalendar also covers tasks.
    Fossify Calendar vs aCalendarFossify Calendar pricing and details

  3. Merkuro Calendar

    Open-source calendar and task app from KDE for Linux

    • Merkuro Calendar is free. aCalendar starts at $2.49 to $11.99 per one-time in-app upgrade; aCalendar+ is $11.99.
    • Only Merkuro Calendar lists a Linux app.
    • Only aCalendar lists an Android app.
    • Merkuro Calendar is open source, according to its own site.
    Merkuro Calendar pricing and details

  4. 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. aCalendar starts at $2.49 to $11.99 per one-time in-app upgrade; aCalendar+ is $11.99.
    • Only Proton Calendar lists a web app.
    • Only Proton Calendar lists macOS, Windows, Linux and iOS apps.
    • Proton Calendar is open source and end-to-end encrypted, according to its own site.
    Proton 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). aCalendar starts at $2.49 to $11.99 per one-time in-app upgrade; aCalendar+ is $11.99.
    • Only Tuta Calendar lists a web app.
    • Only Tuta Calendar lists macOS, Windows, Linux and iOS apps.
    • Tuta Calendar is open source and end-to-end encrypted, according to its own site.
    Tuta Calendar pricing and details

  6. Itsycal

    Free, tiny menu bar calendar for the Mac

    • Itsycal is free. aCalendar starts at $2.49 to $11.99 per one-time in-app upgrade; aCalendar+ is $11.99.
    • Only Itsycal lists a macOS app.
    • Only aCalendar lists an Android app.
    • Itsycal is open source, according to its own site.
    Itsycal pricing and details

  7. MeetingBar

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

    • MeetingBar is free. aCalendar starts at $2.49 to $11.99 per one-time in-app upgrade; aCalendar+ is $11.99.
    • Only MeetingBar lists a macOS app.
    • Only aCalendar lists an Android app.
    • MeetingBar is open source, according to its own site.
    MeetingBar pricing and details

  8. GNOME Calendar

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

    • GNOME Calendar is free. aCalendar starts at $2.49 to $11.99 per one-time in-app upgrade; aCalendar+ is $11.99.
    • Only GNOME Calendar lists a Linux app.
    • Only aCalendar lists an Android app.
    • GNOME Calendar is open source, according to its own site.
    GNOME Calendar pricing and details

  9. Timeful

    Free, open-source group availability poll with calendar autofill

    • Timeful is free. aCalendar starts at $2.49 to $11.99 per one-time in-app upgrade; aCalendar+ is $11.99.
    • Only Timeful lists a web app.
    • Only aCalendar lists an Android app.
    • Timeful is open source and self-hostable, according to its own site.
    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). aCalendar starts at $2.49 to $11.99 per one-time in-app upgrade; aCalendar+ is $11.99.
    • Only Rallly lists a web app.
    • Only aCalendar lists an Android app.
    • Rallly is open source and self-hostable, according to its own site.
    Rallly pricing and details

  11. Crab Fit

    Free, open-source availability heat map for group events

    • Crab Fit is free. aCalendar starts at $2.49 to $11.99 per one-time in-app upgrade; aCalendar+ is $11.99.
    • Only Crab Fit lists a web app.
    • Only Crab Fit lists a browser extension.
    • Crab Fit is open source and self-hostable, according to its own site.
    Crab Fit pricing and details

Common questions

Is there an open-source alternative to aCalendar?

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

Is aCalendar open source?

aCalendar is not described as open source on its own site. The listing was checked on Oct 9, 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 aCalendar: the alternatives its listing names first, then the tools that share the most features with it.