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Best Clustra Calendar Alternatives in 2026

Updated

20 platforms from calendar apps ranked against Clustra Calendar on the same published basis.

  1. 1
    Lark Free plan AndroidapiiOSLinuxMac 8.8
    Clustra Calendar vs Lark
  2. 2
    Calendar.com Free plan AndroidapiextensioniOSWeb $20/mo8.8
    Clustra Calendar vs Calendar.com
  3. 3
    Teamup Free plan AndroidapiiOSWeb $12/mo8.7
    Clustra Calendar vs Teamup
  4. 4
    7shifts Free plan AndroidapiiOSWeb Free8.1
    Clustra Calendar vs 7shifts
  5. 5
    Slotly Free plan AndroidapiWeb $0.83/mo7.9
    Clustra Calendar vs Slotly
  6. 6
    Mozilla Thunderbird Free plan Open sourceAndroidLinuxMacWin Free7.6
    Clustra Calendar vs Mozilla Thunderbird
  7. 7
    Microsoft Outlook Calendar Free plan AndroidiOSMacWeb $1.67/mo7.5
    Clustra Calendar vs Microsoft Outlook Calendar
  8. 8
    Proton Calendar Free plan AndroidiOS Free7.4
    Clustra Calendar vs Proton Calendar
  9. 9
    Reclaim AI Free plan extensionWeb $10/mo7.4
    Clustra Calendar vs Reclaim AI
  10. 10
    EGroupware Free trial Open sourceWebLinuxWinMac €21.90/mo7.4
    Clustra Calendar vs EGroupware
  11. 11
    Notion Calendar Free plan AndroidiOS Free7.3
    Clustra Calendar vs Notion Calendar
  12. 12
    Doodle Free plan Web $11/mo7.3
    Clustra Calendar vs Doodle
  13. 13
    Cozi Free plan AndroidiOSWeb $3.25/mo7.3
    Clustra Calendar vs Cozi
  14. 14
    TimeTree Free plan AndroidiOSWeb $3.75/mo7.3
    Clustra Calendar vs TimeTree
  15. 15
    Google Calendar AndroidiOS $7/mo7.2
    Clustra Calendar vs Google Calendar
  16. 16
    Tuta Calendar Free plan AndroidiOS €3/mo7.2
    Clustra Calendar vs Tuta Calendar
  17. 17
    Fantastical Free plan iOS Free7.2
    Clustra Calendar vs Fantastical
  18. 18
    FlowSavvy Free plan AndroidiOSWeb 7.2
    Clustra Calendar vs FlowSavvy
  19. 19
    Trevor AI Free plan Web $0.42/mo7.2
    Clustra Calendar vs Trevor AI
  20. 20
    Samsung Calendar Free plan Android Free7.1
    Clustra Calendar vs Samsung Calendar

Clustra Calendar alternatives compared

#PlatformScoreFree planFromRuns on
1Lark8.8Free plan—Android, API, iOS, Linux, Mac, Web, Windows
2Calendar.com8.8Free plan$20/moAndroid, API, Browser, iOS, Web
3Teamup8.7Free plan$12/moAndroid, API, iOS, Web
47shifts8.1Free planFreeAndroid, API, iOS, Web
5Slotly7.9Free plan$0.83/moAndroid, API, Web
6Mozilla Thunderbird7.6Free planFreeAndroid, Linux, Mac, Windows
7Microsoft Outlook Calendar7.5Free plan$1.67/moAndroid, iOS, Mac, Web
8Proton Calendar7.4Free planFreeAndroid, iOS
9Reclaim AI7.4Free plan$10/moBrowser, Web
10EGroupware7.4No€21.90/moWeb, Linux, Windows, Mac
11Notion Calendar7.3Free planFreeAndroid, iOS
12Doodle7.3Free plan$11/moWeb
13Cozi7.3Free plan$3.25/moAndroid, iOS, Web
14TimeTree7.3Free plan$3.75/moAndroid, iOS, Web
15Google Calendar7.2No$7/moAndroid, iOS
16Tuta Calendar7.2Free plan€3/moAndroid, iOS
17Fantastical7.2Free planFreeiOS
18FlowSavvy7.2Free plan—Android, iOS, Web
19Trevor AI7.2Free plan$0.42/moWeb
20Samsung Calendar7.1Free planFreeAndroid
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Questions about Clustra Calendar alternatives

What is the best alternative to Clustra Calendar?

Lark, number 1 in calendar apps with a score of 8.8 out of 10. The others here: Calendar.com, Teamup, 7shifts and 16 more.

What is the best free alternative to Clustra Calendar?

Lark is the best-ranked alternative with a free plan. 18 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 on what each maker publishes, open and connectable first: a public API, open-source code, the depth of its documentation and a free tier to try it on. Model lists are sorted by the figure in their title, exactly as each provider publishes it.