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Best OnTime Group Calendar Alternatives in 2026

Updated

20 apps from calendar apps ranked against OnTime Group Calendar on the same published basis.

  1. 1
    Mozilla Thunderbird Free plan Open sourceAndroidLinuxMacWin Free9.0
    OnTime Group Calendar vs Mozilla Thunderbird
  2. 2
    Microsoft Outlook Calendar Free plan AndroidiOSMacWeb $1.67/mo8.2
    OnTime Group Calendar vs Microsoft Outlook Calendar
  3. 3
    Lark Free plan AndroidapiiOSLinuxMac 8.2
    OnTime Group Calendar vs Lark
  4. 4
    EGroupware Free trial Open sourceWebLinuxWinMac €21.90/mo8.2
    OnTime Group Calendar vs EGroupware
  5. 5
    Proton Calendar Free plan AndroidiOS Free8.0
    OnTime Group Calendar vs Proton Calendar
  6. 6
    Teamup Free plan AndroidapiiOSWeb $12/mo8.0
    OnTime Group Calendar vs Teamup
  7. 7
    Cozi Free plan AndroidiOSWeb $3.25/mo8.0
    OnTime Group Calendar vs Cozi
  8. 8
    Calendar.com Free plan AndroidapiextensioniOSWeb $20/mo8.0
    OnTime Group Calendar vs Calendar.com
  9. 9
    TimeFinder Free plan AndroidiOSMacWebWin Free8.0
    OnTime Group Calendar vs TimeFinder
  10. 10
    Notion Calendar Free plan AndroidiOS Free7.9
    OnTime Group Calendar vs Notion Calendar
  11. 11
    TimeTree Free plan AndroidiOSWeb $3.75/mo7.9
    OnTime Group Calendar vs TimeTree
  12. 12
    Fantastical Free plan iOSMacWin Free7.9
    OnTime Group Calendar vs Fantastical
  13. 13
    Doodle Free plan Web $11/mo7.8
    OnTime Group Calendar vs Doodle
  14. 14
    Tuta Calendar Free plan AndroidiOS €3/mo7.8
    OnTime Group Calendar vs Tuta Calendar
  15. 15
    Reclaim AI Free plan extensionWeb $10/mo7.8
    OnTime Group Calendar vs Reclaim AI
  16. 16
    FlowSavvy Free plan AndroidiOSWeb 7.8
    OnTime Group Calendar vs FlowSavvy
  17. 17
    Musubi Free plan AndroidiOSself-hostedWeb Free7.8
    OnTime Group Calendar vs Musubi
  18. 18
    Samsung Calendar Free plan Android Free7.7
    OnTime Group Calendar vs Samsung Calendar
  19. 19
    Trevor AI Free plan Web $0.42/mo7.7
    OnTime Group Calendar vs Trevor AI
  20. 20
    Calendars by Readdle Free plan iOSMac $1.67/mo7.7
    OnTime Group Calendar vs Calendars by Readdle

OnTime Group Calendar alternatives compared

#AppScoreFree planFromRuns on
1Mozilla Thunderbird9.0Free planFreeAndroid, Linux, Mac, Windows
2Microsoft Outlook Calendar8.2Free plan$1.67/moAndroid, iOS, Mac, Web
3Lark8.2Free planAndroid, API, iOS, Linux, Mac, Web, Windows
4EGroupware8.2€21.90/moWeb, Linux, Windows, Mac
5Proton Calendar8.0Free planFreeAndroid, iOS
6Teamup8.0Free plan$12/moAndroid, API, iOS, Web
7Cozi8.0Free plan$3.25/moAndroid, iOS, Web
8Calendar.com8.0Free plan$20/moAndroid, API, Browser, iOS, Web
9TimeFinder8.0Free planFreeAndroid, iOS, Mac, Web, Windows
10Notion Calendar7.9Free planFreeAndroid, iOS
11TimeTree7.9Free plan$3.75/moAndroid, iOS, Web
12Fantastical7.9Free planFreeiOS, Mac, Windows
13Doodle7.8Free plan$11/moWeb
14Tuta Calendar7.8Free plan€3/moAndroid, iOS
15Reclaim AI7.8Free plan$10/moBrowser, Web
16FlowSavvy7.8Free planAndroid, iOS, Web
17Musubi7.8Free planFreeAndroid, iOS, self-hosted, Web
18Samsung Calendar7.7Free planFreeAndroid
19Trevor AI7.7Free plan$0.42/moWeb
20Calendars by Readdle7.7Free plan$1.67/moiOS, Mac
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Questions about OnTime Group Calendar alternatives

What is the best alternative to OnTime Group 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 OnTime Group 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 OnTime Group 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.