Windows 10 reached EOS (end of support) on October 14, 2025. If you are on Windows 10, see this article.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

change font size of panels

  • 2 replies
  • 1 has this problem
  • 115 views
  • Last reply by Alex Hauf
  • Solved

Hello,

how can I change the font size of the folders (sidebar) and the Email list in Thunderbird? I was only able to change the size of the EMail displayed.

Thank you for your help

Hello, how can I change the font size of the folders (sidebar) and the Email list in Thunderbird? I was only able to change the size of the EMail displayed. Thank you for your help

Chosen solution

There is a setting that can change all of the Thunderbird UI. Folder Pane, Thread Pane, Menus, Emails etc.

  • 'Menu icon (3 lines) > Options > Options > Advanced > 'General' tab
  • click on 'Config Editor' button

It may say 'here be dragons' as a type friendly warning to be careful :)

  • In top search type: pixels
  • Look for this line: layout.css.devPixelsPerPx

The default is -1.0

  • Double click on that line to open a small window.
  • clear contents and type in eg: 1.5 or 1.75 or 2.0 or 2.25 etc
  • click on OK

You will see instant effects, so try out different sizes eg: 1.5 or 1.75 or 2.0 or 2.25 etc until you get one that suits you.

Read this answer in context 👍 0

All Replies (2)

Chosen Solution

There is a setting that can change all of the Thunderbird UI. Folder Pane, Thread Pane, Menus, Emails etc.

  • 'Menu icon (3 lines) > Options > Options > Advanced > 'General' tab
  • click on 'Config Editor' button

It may say 'here be dragons' as a type friendly warning to be careful :)

  • In top search type: pixels
  • Look for this line: layout.css.devPixelsPerPx

The default is -1.0

  • Double click on that line to open a small window.
  • clear contents and type in eg: 1.5 or 1.75 or 2.0 or 2.25 etc
  • click on OK

You will see instant effects, so try out different sizes eg: 1.5 or 1.75 or 2.0 or 2.25 etc until you get one that suits you.

Thank you for your help