Proton Calendar vs KOrganizer

Proton Calendar8.8Visit KOrganizer8.6Visit

Higher score Proton Calendar #6 in Calendar Apps 8.8/10 Free plan Free plan✓ 3 of 4 features Try Proton Calendar

vs

KOrganizer #8 in Calendar Apps 8.6/10 Free plan Free plan✓ 1 of 4 features Visit KDE

• Proton Calendar fits best

  Privacy-focused users wanting free scheduling

• KOrganizer fits best

  Linux users needing open-source group calendaring

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Side by side

Feature	Proton Calendar 8.8/10 Visit ↗	KOrganizer 8.6/10 Visit ↗
At a glance
Editor score	8.8	8.6
Ranking	#6 in Calendar Apps	#8 in Calendar Apps
Best for	Privacy-focused users wanting free scheduling	Linux users needing open-source group calendaring
Pricing model	Free plan + paid	Free
Starting price	—	Free plan
Free plan	✓	✓
Free trial	—	—
Deployment	Cloud, Desktop, Mobile	Desktop
Platforms	Web, Windows, macOS, Linux, iOS, Android	Linux
Support	Email, Live chat, Docs	Community, Docs, Email
Integrations	6 integrations	8 integrations
Built for	Solo, Small business, Mid-market, Enterprise	Solo, Small business, Mid-market
Features Proton Calendar 3/4 · KOrganizer 1/4
Shared calendars	✓	✓
Time blocking	Not checked yet	Not checked yet
Scheduling links	✓ (best)	Not checked yet
Video meeting support	✓ (best)	Not checked yet
Specs
Calendar sync	One_way	Two_way
Mobile apps	Ios and android	Not checked yet
Our review
Pros	End-to-end encryption for calendar events Free plan includes recurring events and invitations Booking pages, sharing, and Proton Meet links	Free and open source under the GPL-2.0-or-later license Group scheduling includes invitations, responses, and free/busy data Supports CalDAV, Google Calendar, Nextcloud, Kolab, and more
Cons	External calendar synchronization is one-way Narrower integration set than general-purpose calendars Calendar is bundled with Proton Mail plans	Officially available only as a Linux desktop application No mobile apps for calendar access away from the desktop Does not include verified booking links or time-blocking tools
Our verdict	Proton Calendar is an encrypted calendar service for individuals, families, and teams that want private event management. It supports event creation, recurring schedules, reminders, invitations, sharing, external calendar subscriptions,… Read the review →	KOrganizer is KDE’s calendar and scheduling component for Kontact, designed for Linux desktop users who need more than basic event entry. It brings together events, to-dos, journals, reminders, recurring appointments, multiple calendars,… Read the review →

Strengths and trade-offs

• Proton Calendar — where it wins

  • End-to-end encryption for calendar events
  • Free plan includes recurring events and invitations
  • Booking pages, sharing, and Proton Meet links

  Where it doesn't

  • External calendar synchronization is one-way
  • Narrower integration set than general-purpose calendars
  • Calendar is bundled with Proton Mail plans

• KOrganizer — where it wins

  • Free and open source under the GPL-2.0-or-later license
  • Group scheduling includes invitations, responses, and free/busy data
  • Supports CalDAV, Google Calendar, Nextcloud, Kolab, and more

  Where it doesn't

  • Officially available only as a Linux desktop application
  • No mobile apps for calendar access away from the desktop
  • Does not include verified booking links or time-blocking tools

• Proton Calendar8.8/10 · Free plan

  A privacy-focused calendar with free scheduling tools and limited two-way sync.

  Try Proton CalendarFull verdict →
• KOrganizer8.6/10 · Free plan

  A capable Linux group calendar for users who value open standards and source freedom.

  Visit KDEFull verdict →