KOrganizer review

KOrganizer is the most configurable free calendar on a Linux desktop. KDE describes it as the calendar and scheduling part of Kontact, with events and to-dos, alarm notifications, group scheduling, web export and import and export in the vCalendar and iCalendar formats. It works with Nextcloud, Kolab, Google Calendar and other services, and recent releases fixed CalDAV handling so calendars created in KOrganizer are created on the server and name or color changes sync back. To-dos sit inside the agenda view, events can carry attachments, and the release notes show a steady stream of options, such as hiding holiday categories, showing start and end times in Month view and setting a default to-do calendar. Inside Kontact it shares a window with KMail and KAddressBook, so invitations and contacts connect directly. The cost is complexity: there are many settings, and the app is aimed at Linux, installed through Discover, Flathub or a distribution's package manager. For KDE users who want depth, it is hard to beat.

Who it is for

KDE Plasma users who want a detailed calendar with tasks and printing.

Price

Free and open source as part of Kontact.

180 MiB Download Free
Quoted from the vendor pricing page on November 10, 2026.

Key features

• Multiple calendars and to-do lists with to-dos in the agenda view
• Alarm notifications and group scheduling
• Works with Nextcloud, Kolab, Google Calendar and other services
• Supports vCalendar and iCalendar import and export
• Print support, attachments, and undo and redo

Strengths and weaknesses

• Strength: Free and part of the full Kontact suite with KMail
• Strength: Very configurable views and holiday options
• Strength: Regular releases, with 6.8.3 in November 2026
• Weakness: Linux focused, installed through Discover or a package manager
• Weakness: Many settings can feel dense for new users
• Weakness: The Kontact Flatpak is a 180 MiB download

Key facts

• Price: Free
• Platform: Linux
• Standards: vCalendar, iCalendar, CalDAV
• Suite: Part of Kontact with KMail and KAddressBook

Where it ranks

KOrganizer is No. 6 in our Best Desktop Calendar Apps verdict.