Calendar & Scheduling
Open-source calendar and scheduling apps
11 of the 76 calendar and scheduling apps in this directory are open source, according to their own sites.
All of them are free or have a free plan.
Listings checked up to Oct 9, 2026 · Where the facts come from
| Tool | Price | Free plan | Runs on |
|---|---|---|---|
| Proton CalendarEnd-to-end encrypted calendar from the maker of Proton Mail | Free plan · from $3.99/mo | Yes | Web, macOS, Windows, Linux, iOS, Android |
| RalllyOpen-source meeting polls for finding a time that suits a group | Free plan · from $6/mo | Yes | Web |
| Tuta CalendarEnd-to-end encrypted calendar bundled with Tuta Mail | Free plan · from €3/mo | Yes | Web, macOS, Windows, Linux, iOS, Android |
| ItsycalFree, tiny menu bar calendar for the Mac | Free | Free | macOS |
| MeetingBarFree Mac menu bar app that shows and joins your next meeting | Free | Free | macOS |
| Fossify CalendarOpen-source Android calendar with no ads, tracking or account | Free | Free | Android |
| EtarOpen-source Material Design calendar for Android | Free | Free | Android |
| GNOME CalendarFree, open-source calendar app for the GNOME desktop on Linux | Free | Free | Linux |
| Merkuro CalendarOpen-source calendar and task app from KDE for Linux | Free | Free | Linux |
| Crab FitFree, open-source availability heat map for group events | Free | Free | Web, Android, Browser extension |
| TimefulFree, open-source group availability poll with calendar autofill | Free | Free | Web |
Common questions
Which calendar and scheduling apps are open source?
11 of the 76 calendar and scheduling apps in this directory are open source, according to their own sites. They are Proton Calendar, Rallly, Tuta Calendar, Itsycal, MeetingBar, Fossify Calendar, Etar, GNOME Calendar, Merkuro Calendar, Crab Fit and Timeful.
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 each listing names the pages it was read from.