This article explains how to change the default font in Mozilla Thunderbird for composing new messages. The instructions below apply to Thunderbird for Windows, but the process is similar on Macs.

What to Know

  • Go to Menu > Account Settings > Composition & Addressing and make sure Compose messages in HTML format is checked.Next, select Global Composing Preferences, choose General, then scroll down to Language & Appearance to adjust the font.To change the font when composing a message, select Format > Font.

Change the Default Mozilla Thunderbird Message Font

To set your own default font for composing new messages in Mozilla Thunderbird:

  • Select the menu icon (the three lines) in the upper-right corner, then select Account Settings.
  • Select Composition & Addressing under your email address in the left sidebar.
  • Make sure the Compose messages in HTML format box is checked, then select Global Composing Preferences.
  • Select General in the left sidebar, then scroll down to Language & Appearance to adjust the default font and text size.
  • Select Advanced under Fonts & Colors for more options, including fonts for different languages.
  • Close the Thunderbird settings windows. The change takes effect the next time you compose a message.

Change the Font in Thunderbird Messages

To change the font for an individual email, compose your message and select Format > Font.

Select the menu icon (the three lines) in the upper-right corner, then select Account Settings.

Select Composition & Addressing under your email address in the left sidebar.

Make sure the Compose messages in HTML format box is checked, then select Global Composing Preferences.

Select General in the left sidebar, then scroll down to Language & Appearance to adjust the default font and text size.

Select Advanced under Fonts & Colors for more options, including fonts for different languages.

Close the Thunderbird settings windows. The change takes effect the next time you compose a message.

It’s also possible to change the font for incoming mail in Thunderbird if you want to make your messages easier to read.

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