Free, open-source alternatives to Google Calendar
Google's online calendar. 6 apps you can run yourself instead of Google Calendar, sorted by how well they replace it. Each one is open source, so your data stays with you.
NextcloudBest match
Access and share your files, calendars, contacts, mail and more from any device, on your terms.
Radicale
Simple calendar and contact server with extremely low administrative overhead.
Baïkal
Lightweight CalDAV and CardDAV server based on sabre/dav.
SOGo
SOGo offers multiple ways to access the calendaring and messaging data. CalDAV, CardDAV, GroupDAV, as well as ActiveSync, including native Outlook compatibility and Web interface.
Davis
A simple, dockerizable and fully translatable admin interface for sabre/dav based on Symfony 5 and Bootstrap 4, largely inspired by Baïkal.
Xandikos
Open source CardDAV and CalDAV server with minimal administrative overhead, backed by a Git repository.
Side by side
Why replace Google Calendar?
Google Calendar works, but your data lives in someone else's account, the price can change at any time, and features can disappear. An open-source app you run yourself is yours: you choose where it runs, who can see the data, and when to update.
Questions
What is the best free alternative to Google Calendar?
Nextcloud is the closest open-source replacement for Google Calendar in our list. Radicale and Baïkal are worth a look too, depending on what you need.
Can I self-host an alternative to Google Calendar?
Yes. All 6 apps on this page are open source and can run on your own server, usually with Docker, or on a managed host that installs them for you.