Calendar and Date/Time

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Send Later

True "Send Later" functionality to schedule the time for sending an email.

Rated 5 out of 5 stars (267)
117,600 users

TbSync

TbSync is a central user interface to manage cloud accounts and synchronize their contact, task and calendar information with Thunderbird.

Rated 4 out of 5 stars (271)
55,573 users

Provider for Exchange ActiveSync

Add sync support for Exchange ActiveSync (EAS v2.5 & v14.0) accounts to TbSync

Rated 4 out of 5 stars (63)
29,489 users

Lightning Calendar Tabs

Displays tabs which allows quick navigation between time periods in Lightning calendar. All views of calendar are supported. Color of tab texts can be adjusted.

Rated 4 out of 5 stars (25)
26,272 users

Open Google Calendar

Adds the Google Calendar web interface in a new Thunderbird tab. Creating and viewing events works like in a browser (Firefox, Chrome, ...)

Rated 4 out of 5 stars (80)
22,512 users

Provider for CalDAV & CardDAV

This extension is no longer needed. Thunderbird has native CalDAV and CardDAV support.

Rated 5 out of 5 stars (55)
17,161 users

Google Calendar Tab

Adds a button to open Google Calendar in a new Tab

Rated 4 out of 5 stars (17)
7,866 users

Outlook/Teams Appointments

Get the hidden appointment from an email from outlook/teams as a .ics-file - Icon: https://fontawesome.com/

Rated 3 out of 5 stars (16)
5,711 users

Birthday Calendar

Adds calendars containing the birthdays from your address books.

Rated 4 out of 5 stars (27)
5,017 users

mailmindr

Follow up for Thunderbird E-Mails.

Web: https://mailmindr.net/
Twitter: @mailmindr

Rated 4 out of 5 stars (82)
4,039 users

G-Hub Lite

Google Tabs for Thunderbird! G-Hub Lite supports Calendar, Contacts, Drive, Docs, Sheets, Slides, Maps, Search, & Voice. Need Google Workspace support (formerly G Suite)? Check out G-Hub Pro: https://www.schiffner.com/index.php/software/g-hub-pro

Rated 4 out of 5 stars (24)
3,711 users

ReminderFox Requires Restart

ReminderFox displays and manages lists of reminders and tasks. ReminderFox uses easy-to-use lists with warnings/alarms to remind you of all your important appointments.
Synchronize ReminderFox with other calendars as well.

Rated 4 out of 5 stars (550)
2,511 users

Lightning Invitation Notifier | LIN

This extension is an extension to Mozilla Lightning for Thunderbird.
It shows a toast message and opens the invitations window when an invitation arrives.

Rated 4 out of 5 stars (2)
1,958 users

GCalTab

GCalTab is a Thunderbird add-on that opens Google Calendar website in a Thunderbird tab. It features a beautiful dark mode thanks to the DarkReader algorithm.

Rated 5 out of 5 stars (14)
1,571 users

Proton Calendar Toolbar Button

Adds a Proton Calendar button to the toolbar. The button simply opens a new tab with the https://calendar.proton.me webpage.

Rated 5 out of 5 stars (8)
802 users

More Snooze

This add allow to customize the snooze delay when snooze popup appears (lightning required).

Rated 5 out of 5 stars (10)
751 users

EDS Calendar Integration

Integrates calendars events with Gnome clock applet

Rated 5 out of 5 stars (25)
682 users

Outlook Calendar - Quick Access

This extension adds a simple button to your Spaces toolbar that opens in a new tab, providing you with one-click access to Outlook Calendar.

Rated 3 out of 5 stars (7)
636 users

Macro Template

Macro Template is to replace mail templates with macros for date formatting.

Rated 5 out of 5 stars (9)
594 users

CalendarSearchExport

Exports the results of a search in calendars

Rated 5 out of 5 stars (1)
397 users