Best Open Source Alternatives to Google Calendar

Compare the best free and open-source alternatives to Google Calendar — self-hosted and desktop replacements you fully control, ranked by GitHub stars, license and platform support.

Curated by open-source.store · Updated November 2026 · 7 alternatives

Google Calendar

Proprietary SaaS

PricingFree

Platformsweb, mobile, ios, android

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Google Calendar alternatives compared

Open-source alternatives to Google Calendar, compared by stars, license and platform
Tool		License	Platforms	Self-hosted
Cal.com	49,651	MIT	WebDockerLinuxmacOS	Yes	Nov 2026	Visit
Radicale	5,176	GPL-3.0	LinuxmacOSWindowsDocker	Yes	Nov 2026	Visit
Baïkal	3,360	GPL-3.0	LinuxDockerWeb	Yes	Oct 2026	Visit
SOGo	2,183	GPL-2.0	LinuxDocker	Yes	Nov 2026	Visit
InfCloud	89	AGPL-3.0	Web	Yes	Jul 2024	Visit
DAViCal	0	GPL-2.0	Linux	Yes	—	Visit
Events	0	GPL-3.0	Linux	No	—	Visit

Top open-source Google Calendar alternatives

Cal.com49,651MIT

Cal.com is an open-source scheduling platform replacing Calendar.com with self-hosted booking pages, multi-calendar sync, and automated meeting links.

WebDockerLinuxmacOSWindows

vs Google Calendar: a free, open-source option you fully control, licensed MIT.

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Radicale5,176GPL-3.0

Radicale is a lightweight self-hosted CalDAV and CardDAV server that replaces proprietary cloud calendars with simple file-based storage.

LinuxmacOSWindowsDocker

vs Google Calendar: a free, open-source option you fully control, licensed GPL-3.0.

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Baïkal3,360GPL-3.0

Baïkal is a lightweight CalDAV and CardDAV server replacing Google Calendar sync with fast, private scheduling on SQLite or MySQL.

LinuxDockerWeb

vs Google Calendar: a free, open-source option you fully control, licensed GPL-3.0.

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SOGo2,183GPL-2.0

SOGo replaces Outlook Calendar with a self-hosted groupware suite, offering shared team scheduling and CalDAV sync without per-seat licensing fees.

LinuxDocker

vs Google Calendar: a free, open-source option you fully control, licensed GPL-2.0.

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InfCloud89AGPL-3.0

InfCloud is a self-hosted web client for CalDAV calendars and CardDAV contacts, offering browser scheduling directly on your personal server.

Web

vs Google Calendar: a free, open-source option you fully control, licensed AGPL-3.0.

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Best Open Source Alternatives to Google Calendar

Google Calendar

Google Calendar alternatives compared

Top open-source Google Calendar alternatives

The modern standard for Protobuf workflows

Mentoring for backend developers. Consulting for startups.

More alternatives to Google Calendar

DAViCal

Events