Reduce the size of email headers in Thunderbird with Compact Headers

Martin Brinkmann
Dec 18, 2020
Email, Thunderbird

Compact Headers is a long-standing extension for the open source Thunderbird email client that gives users options to reduce the size of email headers significantly, up to a single line.

thunderbird compact headers


One of the devices that I use Thunderbird on is a Surface Go device; it has a rather small screen and it is quite difficult to read emails in Thunderbird because of the huge header that the client displays in the reading pane. While I could open emails individually to get more space, I tend to read them in the main Thunderbird window as it is faster and more convenient.

The built-in option to reduce the header does not cut it, as the header remains too large for my taste as the headers take up seven lines on the screen in full mode.


thunderbird regular headers

Compact mode, which you can enable under View > Headers, reduces the lines to four. I don't need most information that is displayed in the header, sender and subject are sufficient for my needs.

Compact Headers is an extension for Thunderbird that adds options to the interface to reduce email headers further. It works similarly to the Compact Headers add-on that I reviewed for Thunderbird 3 back in 2009, but is compatible with Thunderbird 78.* unlike the former.

Install Compact Headers in Thunderbird

Here are the instructions to install the extension in the Thunderbird email client:

  1. Open the extension's page on the Thunderbird website.
  2. Download it to the local system.
  3. In Thunderbird, select Tools > Add-ons.
  4. Click on the gear (settings) icon on the page that opens and select Install Add-on from file.
  5. Select the downloaded extension file to install it in Thunderbird.
  6. Confirm the permissions that it requires.

Using Compact Headercompact headers options

Compact Header works right out of the box after you have installed it in the Thunderbird email client. It comes without options on its add-ons page. Everything is managed via the headers toolbar in the client.

Use the arrow icon in the header bar to change the display of headers. You need to right-click on the headers toolbar and select "single line headers" to change the display to a single line that displays the sender's email address and email subject only. There is also an option to hide the entire headers bar to free up even more space.

Closing Words

Compact Headers is a straightforward extension for Thunderbird that is especially useful on devices with smaller displays and for users who tend to read emails in the main window and not individual windows.

Now You: Do you use extensions in Thunderbird? If so which and what do they do?

software image
Author Rating
4 based on 4 votes
Software Name
Compact Headers
Software Category
Landing Page

Tutorials & Tips

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  1. TelV said on February 7, 2021 at 1:01 pm

    Just discovered that the big bottom header can be hidden. Just move the cursor to the dividing line until it becomes a double-headed arrow and then drag it to the bottom of the window.

    The grey bar I was complaining about in my previous post – I don’t see that post anywhere by the way – is caused by the “Quick Filter” button.

    It’s irritating that the T-bird team enables these things in the first place. By all means add stuff, but leave it up to the user to decide whether to enable it or not.

  2. TelV said on February 7, 2021 at 12:45 pm

    It doesn’t work. There’s no context menu and no, what’s described as a “twisty” (whatever the hell that is).

    I want to reduce the bottom header to a single line. Anyone know how to do that?

    Also, how to remove the grey bar containing “Unread”, “Starred”, “Contact”, “Tags”. “Attachment” and the search field. I don’t need any of that crap.

    T-bird version in use is 78.7.1

  3. Norio said on December 22, 2020 at 9:51 pm

    Thanks for pointing this one out! I used to use an extension called CompactHeader but it wasn’t compatible with the latest Thunderbird versions.

  4. Clairvaux said on December 22, 2020 at 5:22 am

    This proves once more how the concept of extensions can be ridiculous. You need an extension just to repair an obvious user interface error which has been there for… how long ? (I’m not a Thunderbird user.)

    Owl’s list shows how absurd this can be. I mean, how old is Thunderbird ? An extension to switch the signature off/on ? Maybe we need an extension to quit the program ? To make the window smaller ?

    This may be fun (for a tiny minority of users), but don’t tell me it’s practical.

    1. owl said on December 23, 2020 at 1:07 am


      I am amazed at your stupid opinion as usual.
      “Extensions” are a “niche” feature that (Indispensable function for many users) Standard specifications lack.

      It is known that @Clairvaux’s favorites are Vivaldi, Vivaldi Mail and Outlook 2004 (End of support risky specifications),
      But Vivaldi’s growth is stagnant due to the concentration of users with (All of them should be added natively, even if they are niche features) such values ​​in Vivaldi (It’s a “Deteriorated user experience product” that is bloated by niche features and continues to add bugs).

      Extensions are sufficient for niche features, and standard specifications should be brushed up (lightened) as much as possible.
      You should be aware that you are ignorant.

  5. owl said on December 19, 2020 at 1:51 am

    Now You: Do you use extensions in Thunderbird? If so which and what do they do?

    All the “extensions”, I’m currently using:
    ● *cloud – FileLink for Nextcloud and ownCloud
    Upload large attachments to your Cloud and send the link by email
    ● Auto Address Cleaner T
    Remove comment, display name from addresses before sending mail.
    Automatically archives old mails (Improved version of the orginal Autoarchive Add-on)
    ● Automatic Dictionary
    ● Birthday Calendar
    Adds calendars containing the birthdays from your address books.
    ● BorderColors D: Shows a colorful border around the “New Message” window, so you can tell different identities apart.
    ● CardBook: address book based on the CardDAV and vCard standards.
    ● Check and Send
    Check the message contents and addresses before you send the message…
    ● Colored Diffs
    Color diffs sent by SVN/CVS/GIT/Mercurial…
    ● Compact Headers
    Limits displayed headers to 1 or 2 lines.
    ● Config Button
    Adds a Config Button, opens about:config in a dialog
    ● Copy Message ID
    Adds a button to the message view toolbar to copy the message ID to the clipboard.
    ● Darko
    Simple dark mode (theme) for your Thunderbird messages.
    ● DeepL selected text
    ● Empty Folder
    Adds a context option to mail folders for moving all included messages to trash.
    ● Enigmail
    OpenPGP message encryption and authentication for Thunderbird.
    ● FileLink Provider for Box
    Uploads your large attachments to your Box instead of sending them by email.
    ● Folder Pane View Switcher
    Folder view arrows; switch to “All Folders” view when hovering during drag & drop; allow user to select which views are enabled or tied to the view arrows.
    ● Full Address column
    Adds a full sender and recipient e-mail column to message list panel.
    ● Identity Chooser
    Identity Chooser helps you to always use the correct identity when composing a new email.
    ● LocalFolders
    Add as many local folders as you want to. New folders can reside on mapped or network locations.
    ● LookOut (fix version)
    LookOut is a plugin which allows Thunderbird to interface with Microsoft’s mail tools by decoding metadata and attachments encapsulated/embedded in a TNEF encoded attachment (aka winmail.dat).
    ● Mail Merge
    Create and Save or Send Multiple Individual and Personalized Messages from a Draft
    ● Manually sort folders
    This extension allows you to manually sort (order) your folders in the folder pane of Thunderbird or automatically sort them. also allows you to re-order accounts in the folder pane.
    ● Minimize on Close
    Causes Thunderbird’s main window to minimize instead of closing. You can still close Thunderbird through the menu.
    ● No Message Pane Sort
    No Message Pane Sort prevents accidental resorting of the message pane by disabling mouse button clicks on the column headers, thus, locking the sorting order of your emails.
    It is still possible to sort messages by ctrl-clicking the header.
    ● Previous Colors
    Quickly choose one of the previously selected colors for a message text
    ● Quicktext
    Lets you create templates that can be easily inserted into your own emails.
    ● Quote Colors
    Configure text and background colors of quotes in mail and news messages.
    ● Remove Duplicate Messages
    Search and remove messages which are the same as other messages in your mail folders (referred to as duplicates or dupes).
    ● Restart Button
    Adds a Restart Button, restarts Thunderbird
    ● ScrollAnywhere
    Features also, “grab and drag” scrolling, customizable scrollbars, the Momentum auto-scroll.
    ● Signature Switch
    Switch the signature on/off or choose a new one from your predefined set.
    ● Spam Scores
    Displays spam scores according to mail headers. Supports spam/ham score headers of Rspamd and SpamAssassin. The add-on adds a column with the overall spam score to the mail list view and shows details of any matched spam/ham rule.
    ● Tag Popup
    You can toggle tags by clicking a tag label in the message header view.
    ● TbSync
    TbSync is a central user interface to manage cloud accounts and synchronize their contact, task and calendar information with Thunderbird.
    ● ThirdStats
    Visualized statistics for your Thunderbird Email Accounts.
    ● Thunderbird Conversations
    This addon provides a conversation view for Thunderbird, grouping messages together and allowing you to reply “inline” thus providing a more efficient workflow.
    ● Web Translate
    Translate the message.
    Supported translators: Google Translate, Microsoft Translator, DeepL, Yandex, Яндекс Переводчик, Google 翻译, 百度翻译.
    ● XNote++
    Persistent sticky notes for Thunderbird associated to mails.

  6. ULBoom said on December 18, 2020 at 10:45 pm

    This is the only extension I use with T Bird beside a theme to give some color.

  7. pwned said on December 18, 2020 at 4:19 pm

    Can I ask, how will this impact phishing scams? I bet it will make it more difficult to detect scammers that put more effort into their phishing emails.

    1. assurbani said on December 19, 2020 at 10:16 am

      sender and recipient are always visible

    2. owl said on December 18, 2020 at 11:48 pm

      @pwned, I bet it will make it more difficult to detect scammers that put more effort into their phishing emails.

      The extension “Compact Headers” is a function that fold the “Displayed headers lines”.
      In Thunderbird Default, “Detailed information” is displayed, so the header occupies 7 lines on the screen, but the extension can simplify it to “Only 1 line is displayed in the header”.
      If you want to see more information, just open it:
      Use the arrow icon in the header bar to change the display of headers.
      By the way, in this extension is also an option to hide the entire headers bar to free up even more space.

    3. ULBoom said on December 18, 2020 at 10:42 pm

      It just collapses the header, doesn’t remove any info from it. Even the normal header display only shows some of the info. If you want all the header info, Menu>View>Headers>All
      shows everything.

      It’s huge!

    4. Martin Brinkmann said on December 18, 2020 at 4:53 pm

      I don’t think it will impact phishing at all, as the hidden information is not helpful when it comes to determine whether an email is a phishing email or not.

      1. pwned said on December 19, 2020 at 9:18 am

        I think this article is a good read

        Note DomainKeys is deprecated now.

        So determining if something phishy is going on or not, via headers is not a farfetched idea.

      2. Martin Brinkmann said on December 19, 2020 at 9:52 am

        I understand that, but the headers that are displayed don’t really help. Looking at the full headers on the other hand is helpful, unless I’m mistaken. Please correct me in that case.

  8. Jeff said on December 18, 2020 at 11:59 am

    The new Thunderbird theme is so God awful. Now a third party colorful theme has become mandatory to use it.

    1. assurbani said on December 19, 2020 at 10:11 am
  9. PD said on December 18, 2020 at 8:10 am

    Is this a MailExtensions version?

    1. Martin Brinkmann said on December 18, 2020 at 4:53 pm

      I think it is.

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