What it does
OneCalendar consolidates appointments from many calendar services. Its official site lists Google, Outlook, Microsoft 365, Exchange, iCloud, CalDAV, Yahoo, GMX, Synology, Nextcloud, ownCloud, and more, plus invitations, recurring events, sharing, offline use, and multiple views.
Connect the calendar services you already use and view their appointments together. OneCalendar lists hosted providers as well as CalDAV, Synology, Nextcloud, and ownCloud. The page also describes recurring events, invitations, sharing, widgets, multiple views, and offline use. It offers downloads for Android, iPhone, iPad, Mac, and Windows. Provider features can differ, so confirm the needs for a particular account before relying on synchronization. The official page calls the app free. No account or offline mode was tested.
Strengths
- The site lists hosted and self-hosted providers, including CalDAV and Nextcloud.
- Appointments can be shared, invited, and repeated.
- The app is listed for Android, iOS, Mac, and Windows.
Watch out for
- Capabilities may vary by connected provider.
Best for
- People combining accounts from several calendar services
- Users needing one view across hosted and self-hosted calendars
Sources
- OneCalendar - Discover the best calendar app of 2026 (Oct 25, 2026)