Best Clustra Calendar Alternatives in 2026
Updated
20 apps from calendar apps ranked against Clustra Calendar on the same published basis.
- 1Clustra Calendar vs Mozilla Thunderbird
- 2Clustra Calendar vs Microsoft Outlook Calendar
- 3Clustra Calendar vs Lark
- 4Clustra Calendar vs EGroupware
- 5Clustra Calendar vs Proton Calendar
- 6Clustra Calendar vs Teamup
- 7Clustra Calendar vs Cozi
- 8Clustra Calendar vs Calendar.com
- 9Clustra Calendar vs TimeFinder
- 10Clustra Calendar vs Notion Calendar
- 11Clustra Calendar vs TimeTree
- 12Clustra Calendar vs Doodle
- 13Clustra Calendar vs Tuta Calendar
- 14Clustra Calendar vs Reclaim AI
- 15Clustra Calendar vs FlowSavvy
- 16Clustra Calendar vs Musubi
- 17Clustra Calendar vs Samsung Calendar
- 18Clustra Calendar vs Fantastical
- 19Clustra Calendar vs Trevor AI
- 20Clustra Calendar vs Calendars by Readdle
Clustra Calendar alternatives compared
| # | App | Score | Free plan | From | Runs on |
|---|---|---|---|---|---|
| 1 | Mozilla Thunderbird | 9.0 | Free plan | Free | Android, Linux, Mac, Windows |
| 2 | Microsoft Outlook Calendar | 8.2 | Free plan | $1.67/mo | Android, iOS, Mac, Web |
| 3 | Lark | 8.2 | Free plan | — | Android, API, iOS, Linux, Mac, Web, Windows |
| 4 | EGroupware | 8.2 | No | €21.90/mo | Web, Linux, Windows, Mac |
| 5 | Proton Calendar | 8.0 | Free plan | Free | Android, iOS |
| 6 | Teamup | 8.0 | Free plan | $12/mo | Android, API, iOS, Web |
| 7 | Cozi | 8.0 | Free plan | $3.25/mo | Android, iOS, Web |
| 8 | Calendar.com | 8.0 | Free plan | $20/mo | Android, API, Browser, iOS, Web |
| 9 | TimeFinder | 8.0 | Free plan | Free | Android, iOS, Mac, Web, Windows |
| 10 | Notion Calendar | 7.9 | Free plan | Free | Android, iOS |
| 11 | TimeTree | 7.9 | Free plan | $3.75/mo | Android, iOS, Web |
| 12 | Doodle | 7.8 | Free plan | $11/mo | Web |
| 13 | Tuta Calendar | 7.8 | Free plan | €3/mo | Android, iOS |
| 14 | Reclaim AI | 7.8 | Free plan | $10/mo | Browser, Web |
| 15 | FlowSavvy | 7.8 | Free plan | — | Android, iOS, Web |
| 16 | Musubi | 7.8 | Free plan | Free | Android, iOS, self-hosted, Web |
| 17 | Samsung Calendar | 7.7 | Free plan | Free | Android |
| 18 | Fantastical | 7.7 | Free plan | Free | iOS |
| 19 | Trevor AI | 7.7 | Free plan | $0.42/mo | Web |
| 20 | Calendars by Readdle | 7.7 | Free plan | $1.67/mo | iOS, Mac |
Make your app an alternative to Clustra Calendar
See the priceThe sponsored alternative slot on this page is labelled Sponsored.
Questions about Clustra Calendar alternatives
What is the best alternative to Clustra Calendar?
Mozilla Thunderbird, number 1 in calendar apps with a score of 9.0 out of 10. The others here: Microsoft Outlook Calendar, Lark, EGroupware and 16 more.
What is the best free alternative to Clustra Calendar?
Mozilla Thunderbird is the best-ranked alternative with a free plan. 19 of the 20 alternatives here publish a free plan on their own pricing pages.
Is there an open-source alternative to Clustra Calendar?
Yes: Mozilla Thunderbird, EGroupware.
How are these alternatives ranked?
Ranked free-and-open first: a usable free tier and open-source code, then the platforms it runs on and its documentation.