OneCalendar
by OneCalendar
What OneCalendar is
OneCalendar is a calendar app from OneCalendar for managing appointments, meetings, recurring events, and shared schedules. It connects with Google Calendar, Outlook, Office 365, Exchange, iCloud, CalDAV, Yahoo, GMX, Synology, Nextcloud, ownCloud, and Mailbox.org. You can add, change, remove, search, and repeat appointments, invite people, and respond to invitations. Day, week, month, year, and list or agenda views cover different ways to review a calendar. Appointments remain viewable and manageable without an internet connection. Customization includes calendar and appointment colors, configurable widgets, background pictures, text colors, 170 color options, and a dark theme. The free Basic plan provides calendar viewing and management, multiple providers and views, and appointment sharing. Premium adds features such as search, immediate synchronization, navigation, and up to three years of appointment history instead of six months. OneCalendar runs on Android, iOS, macOS, and Windows.
Who it suits
It suits people who combine calendars from several providers and need shared, recurring, or offline appointment management. It also fits users wanting calendar views and appearance settings across desktop and mobile platforms.
What it does well
- Supports many calendar providers
- Works offline for appointment management
- Offers multiple calendar views
- Includes appointment sharing
- Available on four platforms
What to know first
- Premium limits history to six months on usual plan
- Premium features have no listed price
- Some premium features are Windows 10/11 only
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| Basic | Synchronizes up to 6 months of appointment history | Free |
| Premium | License required separately for Android, iOS, and Windows; valid on devices using the same platform and store account | On request |
As onecalendar.nl lists them, read 12 Oct 2026. The maker's own page has the final word.
Verdict
OneCalendar combines broad provider support with offline management, sharing, recurring events, and several calendar views. Its free plan covers core calendar work, while appearance, search, synchronization, and longer history are assigned to Premium.
Facts from OneCalendar's own pages
- Appointment tools
- Users can add, update, and delete appointments, set recurrences, invite people, accept invitations, and search appointments. · onecalendar.nl, 12 Oct 2026
- Calendar services
- It supports Google Calendar, Outlook, Office 365, Exchange, iCloud, CalDAV, Yahoo, GMX, Synology, Nextcloud, ownCloud, and Mailbox.org. · onecalendar.nl, 12 Oct 2026
- Calendar views
- Available views include day, week, month, year, and list or agenda. · onecalendar.nl, 12 Oct 2026
- Customization
- Features include calendar and appointment colors, configurable widgets, and theming with 170 color options, background pictures, text colors, and a dark theme. · onecalendar.nl, 12 Oct 2026
- Free plan
- Yes · onecalendar.nl, 21 Sept 2026
- Headquarters
- Heemskerk, Netherlands · onecalendar.nl, 28 Sept 2026
- Mobile apps
- ios and android · onecalendar.nl, 21 Sept 2026
- Offline use
- The app can view and manage appointments without an internet connection. · onecalendar.nl, 12 Oct 2026
- Platforms
- The download page lists Android 6 and higher, iPhone, iPad, Mac, and Windows 10 and 11. · onecalendar.nl, 12 Oct 2026
- Premium features
- Premium adds appointment colors, theming, search, configurable widgets, immediate synchronization, navigation, and up to three years of appointment history instead of the usual six months. · onecalendar.nl, 12 Oct 2026
- Premium limits
- Printing, automatic day rollover, and hiding promotional windows are listed as Windows 10/11-only Premium features. · onecalendar.nl, 12 Oct 2026
- Privacy
- The privacy policy says appointment and birthday information is not stored on OneCalendar servers and synchronization happens directly between the device and calendar provider. · onecalendar.nl, 12 Oct 2026
- Purpose
- OneCalendar lets users manage appointments, set up recurring events and meetings, and share appointments. · onecalendar.nl, 12 Oct 2026
- Security
- For Google and Microsoft accounts, OneCalendar uses OAuth 2.0 over HTTPS and stores received tokens encrypted on the device; its security page also says iCloud passwords and Exchange credentials are stored encrypted on the device. · onecalendar.nl, 12 Oct 2026
- Support
- The support page provides separate email addresses for Windows, Android, iOS, and macOS users, plus a general support address. · onecalendar.nl, 12 Oct 2026
Where OneCalendar stands on Freedom251
- Calendar apps#35 of 194