Google Calendar
Free
Google Calendar is a cloud based calendar from Google.
Evolution
Open Source
Evolution is the official personal information manager for GNOME.
Rainlendar
Freemium
Rainlendar is a calendar program for Windows, Mac OS X and Linux.
Kontact
Open Source
Kontact is a personal information manager and groupware software suite developed by KDE. It supports calendars, contacts, notes, to-do lists, news, and email.
Microsoft Mail and Calendar apps help you stay up to date on your email, manage your schedule and stay in touch with people you care about the most.
Lightning
Open Source
Lightning App Builder is a point-and-click tool that makes it easy to create custom pages for Salesforce1 and Lightning Experience.
Apple Calendar
Free
Calendar is a personal calendar application made by Apple Inc. that runs on both the macOS desktop operating system and iOS mobile operating system.
Org-mode
Open Source
Org-mode is an Emacs Mode for Notes, Planning, and Authoring.
VueMinder Calendar
Freemium
VueMinder Calendar is a calendar app for Windows.
Compare Kontact - KOrganizer with alternatives
Compare Google Calendar and Kontact - KOrganizer and decide which is most suitable for you.
Compare Lightning and Kontact - KOrganizer and decide which is most suitable for you.
Compare Evolution and Kontact - KOrganizer and decide which is most suitable for you.
Compare Apple Calendar and Kontact - KOrganizer and decide which is most suitable for you.
Compare Rainlendar and Kontact - KOrganizer and decide which is most suitable for you.
Compare Org-mode and Kontact - KOrganizer and decide which is most suitable for you.
Compare Kontact and Kontact - KOrganizer and decide which is most suitable for you.
Compare VueMinder Calendar and Kontact - KOrganizer and decide which is most suitable for you.
Compare Microsoft Mail and Calendar and Kontact - KOrganizer and decide which is most suitable for you.