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 (264)
105,936 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 (263)
64,664 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 (60)
31,763 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)
26,502 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)
23,939 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 (78)
21,999 users

Google Calendar Tab

Adds a button to open Google Calendar in a new Tab

Rated 4 out of 5 stars (17)
7,932 users

Outlook/Teams Appointments

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

Rated 4 out of 5 stars (13)
5,263 users

Birthday Calendar

Adds calendars containing the birthdays from your address books.

Rated 5 out of 5 stars (23)
4,953 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 (23)
3,804 users

mailmindr

Follow up for Thunderbird E-Mails.

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

Rated 4 out of 5 stars (79)
3,578 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)
2,740 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)
2,111 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 (12)
1,733 users

EDS Calendar Integration

Integrates calendars events with Gnome clock applet

Rated 5 out of 5 stars (25)
752 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)
746 users

More Snooze

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

Rated 5 out of 5 stars (10)
716 users

Macro Template

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

Rated 5 out of 5 stars (9)
508 users

M-Hub Lite

Add Microsoft Office 365 Tabs to Thunderbird! Services supported by M-Hub Lite: Calendar, People, OneDrive, Word, Excel, PowerPoint, & Bing. Need business or enterprise support? Get M-Hub Pro: https://www.schiffner.com/software/m-hub-pro

Rated 3 out of 5 stars (5)
308 users

Lightning Colors Reminder Requires Restart

Let's show the calendar color on Lightning reminders!

Rated 4 out of 5 stars (4)
242 users