European Alternatives to Outlook Calendar
Calendar integrated with Outlook and Microsoft 365. Deep sync with Teams, Word, Excel and the Microsoft ecosystem.
Outlook Calendar Features
- Free with an Outlook.com account
- Sync across Teams, Office, OneDrive
- Copilot integrated into Calendar (since May 2026)
- Web, Windows/macOS desktop, Android, iOS apps
- 15 GB Outlook.com storage
- Proprietary source code
Price: Free (with Outlook.com) / Microsoft 365 Personal from 7€/month
Why leave Outlook Calendar?
- Microsoft Copilot accesses your calendar by default (daily briefing, double-booking detection) since May 2026
- Microsoft Corporation is headquartered in Redmond (United States) and subject to the US CLOUD Act
- Microsoft 365 price hike of 5% to 33% effective July 2026
- Windows and Outlook telemetry enabled by default on all accounts
- Copilot improvements may use your content unless your admin explicitly opts out
Recommended : Tuta Calendar
The most encrypted calendar on the market: titles, dates, times and guests all encrypted in zero-knowledge. Quantum-safe encryption. Dedicated standalone iOS/Android apps.
Country : DE
Compatibility Scores
- Migration : 80/100
- GDPR : 100/100
- Features : 85/100
- Overall Score : 89/100
Tuta Calendar Features
- Free tier available
- Quantum-safe encryption on everything (including dates/times)
- Standalone iOS/Android apps (separate from Tuta Mail)
- Bundle with E2E Mail + Calendar + Contacts
- ISO 27001 datacenters in Germany
- Open-source code
Price: Free / Revolutionary at 3€/month / Legend at 8€/month
Why this choice?
Tuta Calendar is our recommendation for Outlook Calendar users thanks to its ISO 27001 certification and quantum-safe encryption on everything (titles, dates, times, guests). It's the most rigorous solution on the European compliance side, hosted in Germany and outside the CLOUD Act, without the Microsoft 365 price hike planned for July 2026.
Switch from Outlook Calendar to Tuta Calendar
Strengths
- ISO 27001 certification (like Microsoft) plus quantum-safe encryption
- No Copilot accessing your calendar by default
- Germany hosting aligned with EU Data Boundary
- Dedicated standalone iOS/Android apps
- No scheduled price hike (vs +5-33% on M365)
Weaknesses
- No native Office/Teams integration
- Limited bundle (Tuta is mail + calendar only)
- More minimalist UI than Outlook
All Alternatives
- Tuta Calendar (DE) — Score : 89/100 (Recommended)
- Proton Calendar (CH) — Score : 88/100
- Infomaniak Calendar (CH) — Score : 81/100