Calendar and Date/Time

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Lightning Requires Restart

Organize your schedule and life's important events in a calendar that's fully integrated with your Thunderbird email. Manage multiple calendars, create your daily to do list, invite friends to events, and subscribe to public calendars.

Rated 3 out of 5 stars (2,088)
5,731,838 users

Send Later Requires Restart

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

Rated 5 out of 5 stars (195)
66,939 users

TbSync

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

Rated 5 out of 5 stars (122)
53,494 users

Provider for CalDAV & CardDAV

This extension adds support for CalDAV & CardDAV accounts to the Thunderbird Sync manager "TbSync". Including iCloud, Google, ownCloud, Nextcloud, Radicale and many more.

Rated 5 out of 5 stars (28)
33,013 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 (54)
25,464 users

Provider for Exchange ActiveSync

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

Rated 5 out of 5 stars (17)
22,960 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 (15)
21,566 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 (549)
8,997 users

Google Calendar Tab

Adds a button to open Google Calendar in a new Tab

Rated 5 out of 5 stars (7)
6,706 users

G-Hub Lite

Add Google Tabs to Thunderbird! Services supported by G-Hub Lite: Calendar, Contacts, Drive, Docs, Sheets, Slides, Maps, Search, & Voice. Need G Suite / Google Apps support? Check out G-Hub Pro: https://www.schiffner.com/index.php/software/g-hub-pro

Rated 4 out of 5 stars (16)
5,549 users

Lightning Colors Reminder Requires Restart

Let's show the calendar color on Lightning reminders!

Rated 4 out of 5 stars (3)
3,127 users

Lightning Invitation Notifier Requires Restart

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)
1,796 users

Todo.txt Requires Restart

Thunderbird extension for the Todo.txt application

Rated 4 out of 5 stars (13)
744 users

More Snooze Requires Restart

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

Rated 5 out of 5 stars (7)
608 users

EDS Calendar Integration Requires Restart

Integrates calendars events with Gnome clock applet

Rated 4 out of 5 stars (13)
607 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 (4)
483 users

Custom sync interval for Lightning Calendar Requires Restart

Allows custom synchronization intervals for remote calendars imported by Lightning Calendar (no fiddling in about:config necessary)

Rated 5 out of 5 stars (1)
468 users

OBM Connector Requires Restart

OBM Lightning Calendar and addressbooks connector

Not yet rated
391 users

Purge Events Plus Requires Restart

Purge events from Sunbird and Lightning files and thereby cleanes the calendar

Rated 4 out of 5 stars (9)
328 users

Gantt View Requires Restart

Gantt Chart view for Sunbird/Lightning

Rated 4 out of 5 stars (34)
319 users