Best Mozilla Thunderbird Alternatives in 2026
Updated
20 apps from calendar apps ranked against Mozilla Thunderbird on the same published basis.
- 2Mozilla Thunderbird vs Microsoft Outlook Calendar
- 3Mozilla Thunderbird vs Lark
- 4Mozilla Thunderbird vs EGroupware
- 5Mozilla Thunderbird vs Proton Calendar
- 6Mozilla Thunderbird vs Teamup
- 7Mozilla Thunderbird vs Calendar.com
- 8Mozilla Thunderbird vs Notion Calendar
- 9Mozilla Thunderbird vs Doodle
- 10Mozilla Thunderbird vs Tuta Calendar
- 11Mozilla Thunderbird vs Cozi
- 12Mozilla Thunderbird vs TimeTree
- 13Mozilla Thunderbird vs Reclaim AI
- 14Mozilla Thunderbird vs FlowSavvy
- 15Mozilla Thunderbird vs TimeFinder
- 16Mozilla Thunderbird vs Samsung Calendar
- 17Mozilla Thunderbird vs Fantastical
- 18Mozilla Thunderbird vs Calendars by Readdle
- 19Mozilla Thunderbird vs Vyte
- 20Mozilla Thunderbird vs DayOtter
- 21Mozilla Thunderbird vs Daybridge
Mozilla Thunderbird alternatives compared
| # | App | Score | Free plan | From | Runs on |
|---|---|---|---|---|---|
| 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 | Calendar.com | 8.0 | Free plan | $20/mo | Android, API, Browser, iOS, Web |
| 8 | Notion Calendar | 7.9 | Free plan | Free | Android, iOS |
| 9 | Doodle | 7.8 | Free plan | $11/mo | Web |
| 10 | Tuta Calendar | 7.8 | Free plan | €3/mo | Android, iOS |
| 11 | Cozi | 7.8 | Free plan | $3.25/mo | Android, iOS, Web |
| 12 | TimeTree | 7.8 | Free plan | $4.49/mo | Android, iOS |
| 13 | Reclaim AI | 7.8 | Free plan | $10/mo | Browser, Web |
| 14 | FlowSavvy | 7.8 | Free plan | — | Android, iOS, Web |
| 15 | TimeFinder | 7.8 | Free plan | Free | Web, Windows, Mac, iOS, Android |
| 16 | Samsung Calendar | 7.7 | Free plan | Free | Android |
| 17 | Fantastical | 7.7 | Free plan | Free | iOS |
| 18 | Calendars by Readdle | 7.6 | Free plan | $1.67/mo | iOS |
| 19 | Vyte | 7.6 | Free plan | $8/mo | Web, iOS |
| 20 | DayOtter | 7.6 | Free plan | $9/mo | Web, Android |
| 21 | Daybridge | 7.6 | Free plan | Free | Android, iOS |
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Questions about Mozilla Thunderbird alternatives
What is the best alternative to Mozilla Thunderbird?
Microsoft Outlook Calendar, number 2 in calendar apps with a score of 8.2 out of 10. The others here: Lark, EGroupware, Proton Calendar and 16 more.
What is the best free alternative to Mozilla Thunderbird?
Microsoft Outlook Calendar 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 Mozilla Thunderbird?
Yes: 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.