'''Edit: As of 2023, layout.css.devPixelsPerPx is no longer supported starting with version 115. Anything other than the default -1.0 may cause problems. See https://support.mozilla.org/en-US/kb/thunderbird-115-supernova-faq#w_why-are-the-fonts-still-too-large-or-too-small-after-i-changed-the-density-and-font-size ''' Do you mean the font in general is tiny ? The Folder Pane folder font, the Thread Pane list of emails font and when you select emails, the content of email is tiny ? If you want to increase the font in everything then do this: * Menu app icon > Options/Preferences > General * Scroll down to the very bottom * click on 'Config Editor' button to open 'about:config' * Accept the risk. * In search type: '''pixels''' * Look for this line: '''layout.css.devPixelsPerPx''' * Double left click on that line to open the 'Enter string Value' box so you can edit the Value. The default value will be a negative number: -1.0 * Enter a new positive number eg: 1.25 or 1.5 or 2.0 or 2.2 * click on OK the effect is immediate, so you can modify that number until it looks ok for you. Image below as guide. ------------------------------------------------------ '''Or''' do you mean only the font in the content of selected emails is tiny? Is it tiny in all emails or some ok and some tiny? Check your font size settings: * Menu app icon > Options/Preferences > General * Scroll to 'Language & Appearance' section * Under 'Fonts & colours' * click on 'Advanced' button I'm presuming you are using 'Latin'. 'Fonts for:' 'Latin' Set 'Proportional Size', Monospace Size' and 'Minimum font size' to 14 (or 16 if you prefer a bit larger) Then select the 'Fonts for:' 'Other Writing Systems' Set 'Proportional Size', Monospace Size' and 'Minimum font size' to 14 (or 16 if you prefer a bit larger) click on OK Restart Thunderbird Report back on results.

Thank you! The pixels change is what I needed. Very much appreciated!!