Tuta Calendar vs UCals

Tuta Calendar organizes appointments, business meetings, and repeating tasks across Android, iOS, Linux, macOS, web, and Windows. It supports shared calendars with read-only, read-and-write, or write-and-manage-sharing access. Calendar events, invitations, sharing, and push reminders are described as end-to-end encrypted. Users can send and receive invitations, including password-protected encrypted invitations to external users. Imported calendars sync automatically across devices, while the listed calendar sync type is one-way. Tuta says reminders are hidden from the phone operating system and can arrive offline. The calendar is integrated with Tuta email and contacts. Security features include two-factor authentication; Tuta also describes its clients as open source and its calendar as using zero-knowledge architecture. The Free plan includes one calendar. Revolutionary costs €3 a month, billed monthly, and Legend costs €8 a month, billed monthly; both include unlimited calendars. Tuta is made by Tutao GmbH, based in Hannover, Germany, and founded in 2011.

UCals is an AI calendar assistant that manages schedules through natural-language conversation. One instruction can make multiple calendar changes, and later messages can use earlier conversational context. Its plan covers 11 life categories, including work, meals, exercise, and travel. Two-way synchronization is available with Google Calendar, Apple Calendar, and Microsoft Outlook. Tools include conflict detection, travel-time calculation, multi-currency cost tracking, location intelligence, learned preferences, and linked events. UCals displays before-and-after details for changes, and saying “undo” reverts the last change. Its MCP server connects calendars to Claude Desktop, ChatGPT, Cursor, and other compatible assistants. Platforms listed are Android, iOS, macOS, Windows, and an API. UCals says it uses OAuth 2.0, does not store calendar passwords, encrypts data in transit and at rest, and does not sell, share, or train on calendar data. ICS export and priority support are included. A 14-day trial is offered. The Single plan costs $15 a month, billed monthly.