How do I change the default font size for reading the body of messages in Mail 6.0? I know that I can use ctrl++, but I want the reading pane to default the body of the message to a larger font without lowering the default resolution.

  • Can I bump this question? the defaults write com.apple.mail MinimumHTMLFontSize method no longer works
    – user39008
    Mar 2, 2021 at 15:33

2 Answers 2


This is a setting that can be changed in Mail Preferences. Open the dialog box by clicking:

Mail > Preferences (or Cmd + ,) > Fonts & Colors > Message Font > Select...

A dialog box should display with text options for you to customize.

  • That only changes the message font for my outgoing messages. It has no effect on the size of the font for the body of the incoming message.
    – Jeff
    Nov 7, 2012 at 2:52
  • Interesting. I tested it, and it increased the font size for all my message content (incoming and outgoing, header info, and body). One very important thing to note, is that there is no way to change the font size of incoming HTML emails. For example, emails such as receipts, or shipping confirmation from Amazon.com will not be affected by your customizations. On the other hand, all normal text emails will be adjusted. Nov 7, 2012 at 3:22
  • Any other suggestions?
    – Jeff
    Nov 7, 2012 at 23:50
  • Some messages are in a large enough font. The majority are still small. Could it be that almost all incoming messages are in HTML? I can still increase the reading size by cntrl + on the small font messages.
    – Jeff
    Nov 7, 2012 at 23:52
  • It's entirely possible. If the emails with small text come from online retailers, they're probably HTML, if they're from an individual, they probably adjustable font size. Send yourself a test message, then change the font, and see if it changes the message that you received from yourself. Nov 8, 2012 at 0:00

I just tried this and it worked for me: http://www.pitt.edu/~hunter3/ComputerHelp/mailappfont.htm

How to permanently change the font size of the body of emails in Mac OS X's Mail program (i.e. manually get past missing font option for that reading or preview pane).

Command and A, then Command and + will increase the font size in the reading or preview pane of Mail.app, but how to make that larger size the default? If you go into the Preferences (in the Mail menu), there is a font section where you can customize font family and size for just about everything but that reading pane (crazy oversight).

First close Mail.app, then go to the Go menu (when in Finder or just click on any blank area of your desktop) and select Utilities, the double-click Terminal, then type defaults write com.apple.mail MinimumHTMLFontSize 14 then hit enter/return then reopen Mail.app to make sure the changes have been made.

Note: the default is 12, and if you want larger than 14, just replace that number with whatever font size you want.

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