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Google Calendar alternatives · Calendar

Open-source alternatives to Google Calendar

Google 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.

Google Calendar has a free plan. Paid plans start at $7 per user / month with a 1-year commitment (Workspace Business Starter). 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 Google Calendar

  1. 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. Google Calendar starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only Proton Calendar lists macOS, Windows and Linux apps.
    • Proton Calendar is open source and end-to-end encrypted, according to its own site.
    • Google Calendar also covers tasks.
    Proton Calendar pricing and details

  2. Merkuro Calendar

    Open-source calendar and task app from KDE for Linux

    • Merkuro Calendar is free. Google Calendar starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only Merkuro Calendar lists a Linux app.
    • Only Google Calendar lists a web app.
    • Only Google Calendar lists iOS and Android apps.
    Merkuro Calendar pricing and details

  3. Tuta Calendar

    End-to-end encrypted calendar bundled with Tuta Mail

    • Tuta Calendar starts at €3 per month, paid yearly (€3.60 paid monthly). Google Calendar starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only Tuta Calendar lists macOS, Windows and Linux apps.
    • Tuta Calendar is open source and end-to-end encrypted, according to its own site.
    • Google Calendar also covers tasks and booking links.
    Tuta Calendar pricing and details

  4. Itsycal

    Free, tiny menu bar calendar for the Mac

    • Itsycal is free. Google Calendar starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only Itsycal lists a macOS app.
    • Only Google Calendar lists a web app.
    • Only Google Calendar lists iOS and Android apps.
    Itsycal pricing and details

  5. MeetingBar

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

    • MeetingBar is free. Google Calendar starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only MeetingBar lists a macOS app.
    • Only Google Calendar lists a web app.
    • Only Google Calendar lists iOS and Android apps.
    MeetingBar pricing and details

  6. Fossify Calendar

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

    • Fossify Calendar is free. Google Calendar starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only Google Calendar lists a web app.
    • Only Google Calendar lists an iOS app.
    • Fossify Calendar is open source, according to its own site.
    Fossify Calendar pricing and details

  7. Etar

    Open-source Material Design calendar for Android

    • Etar is free. Google Calendar starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only Google Calendar lists a web app.
    • Only Google Calendar lists an iOS app.
    • Etar is open source, according to its own site.
    Etar pricing and details

  8. GNOME Calendar

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

    • GNOME Calendar is free. Google Calendar starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only GNOME Calendar lists a Linux app.
    • Only Google Calendar lists a web app.
    • Only Google Calendar lists iOS and Android apps.
    GNOME Calendar pricing and details

  9. Timeful

    Free, open-source group availability poll with calendar autofill

    • Timeful is free. Google Calendar starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only Google Calendar lists iOS and Android 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). Google Calendar starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only Google Calendar lists iOS and Android apps.
    • Rallly is open source and self-hostable, according to its own site.
    • Google Calendar also covers tasks, calendar and booking links.
    Rallly pricing and details

  11. Crab Fit

    Free, open-source availability heat map for group events

    • Crab Fit is free. Google Calendar starts at $7 per user / month with a 1-year commitment (Workspace Business Starter).
    • Only Crab Fit lists a browser extension.
    • Only Google Calendar lists an iOS app.
    • 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 Google Calendar?

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

Is Google Calendar open source?

Google Calendar is not described as open source on its own site. The listing was checked on Oct 4, 2026 against the pages it cites.

When was this checked?

Each listing shows its own date. On this page they run from Oct 4, 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 Google Calendar: the alternatives its listing names first, then the tools that share the most features with it.