Enlarge font in the Reading Pane

Using a high resolution has the benefit of a sharper display which is more relaxed for your eyes. The downside of this is that your font might become really small and hard to read which is anything but relaxed for your eyes.

There are several ways to enlarge the font in the Reading Pane in Outlook;

Method 1: Zoom in on the message

You can use CTRL+Mouse Scroll in the Reading Pane to zoom in and out per message. Depending on your mouse/scroll sensitivity you might need to scroll quite a bit before the font size will change.

You can also zoom via the zoom slider in the bottom right corner.

When you are using Outlook for Microsoft 365, you can click on the percentage indicator next to the slider (in this case 100%) to set a persistent zoom factor by enabling the option; Remember my preference.

Note: In other version of Outlook, the zooming factor set via this slider or by scrolling is not persistent. To still set a default zooming level for these Outlook versions, you can use the add-in Zoom Email Windows from Sperry Software (discount code BH93RF24 ).

Method 2: Customize the font size for Plain Text messages

For Plain Text you can modify the display font via;

• Outlook 2007
  Tools-> Options…-> tab Mail Format-> button Stationery and Fonts
• Outlook 2010 / 2013 / 2016 / 2019 / Microsoft 365
  File-> Options-> section Mail-> button Stationery and Fonts

Method 3: Convert HTML messages to Plain Text

Another way to go for HTML formatted emails would be to set the option to read all mail in Plain Text. Together with your modified Plain Text font settings, the larger font size will always apply.

Via the Infobar, which will display on top of a converted message, you can easily change it back to HTML format when needed (like for some special layout or newsletters).

To configure Outlook to display all the email in Plain Text by default;

• Outlook 2007
  Tools-> Trust Center…-> E-mail Security-> Read all standard mail in plain text
• Outlook 2010 / 2013 / 2016 / 2019 / Microsoft 365
  File-> Options-> section Trust Center-> button Trust Center Settings…-> E-mail Security-> Read all standard mail in plain text

Convert messages back to HTML.

Method 4: Changing the scaling or DPI settings in Windows

If font sizes is a general issue throughout Outlook, Windows and other applications, you might want to consider customizing the scaling or DPI settings in Windows instead.

This is especially recommended when you are using a smaller screen with a high resolution and also on a larger screen with a 4K, 5K or higher resolution.

Windows 10

1. Right click on an empty spot on your Desktop and choose: Display Settings.
2. You can set the text scaling percentage in the section: Change the size of text, apps, and other items
   • To set a custom scaling percentage, press the “Advanced scaling settings” shown in the same dialog.

Scale and layout settings in Windows 10.

Windows 7 and Windows 8

1. Right click on an empty spot on your Desktop and choose: Screen resolution.
2. Click on the blue text link: Make text and other items larger or smaller.
3. Here you can directly set your DPI settings to 125%.
   To set a custom DPI value:
   • Windows 7
     Use the “Set custom text size (DPI)” link in the Task Pane on the left.
   • Windows 8 and Windows 8.1
     Use the “Custom sizing options” text link below the presets.
   • Windows 8.1 with multiple monitors
     Select the option “Let me choose one scaling level for all my displays”.
4. In the new dialog that pops up you can directly choose a predefined value to make the fonts bigger.You can also type any percentage you like.

Zoom your interface to a readable size for your screen.

Note 1: You can actually TYPE a percentage; you don't have to use the predefined values in the dropdown list.

Note 2: In Windows 7 and Windows 8, if you have the issue that some text will fall out of dialogs after increasing the DPI settings, you can press the "Custom DPI..." button and deselect the option "Use Windows XP style DPI scaling". This does some pretty nifty dialog re-rendering but I won't bore you with technical details on that ;-)

Note 3: More Outlook font, size and color customizations can be found in the guide; Fonts, sizes and color settings of the Outlook interface.