How to Change the Font Size in Outlook Email

Font size in Outlook isn't a single setting buried in one menu — it shows up in several different places, each controlling a different part of your email experience. Changing the font size in a message you're composing is a different action than changing how received emails display on your screen, which is different again from changing the default font for all new emails going forward. Understanding which layer you're actually trying to adjust makes the whole process much clearer.

The Three Layers of Font Size in Outlook

Most people searching this question are actually dealing with one of three distinct scenarios:

• Composing font size — the size of text as you type a new message
• Reading font size — how incoming emails appear on your screen
• Default font size — the size Outlook uses automatically every time you start a new email or reply

Each one is controlled separately, and changing one doesn't affect the others.

Changing Font Size While Composing a Message

This is the most immediate adjustment. When you're typing a new email in Outlook (desktop app), the Format Text tab in the ribbon gives you direct access to font controls — including a numeric font size box where you can type any size or use the dropdown to pick from a standard list.

You can also highlight existing text and use the Home tab in the message window. Look for the font size field next to the font name — it works the same way as in Microsoft Word.

Keyboard shortcuts speed this up:

• Ctrl + Shift + > increases font size one step
• Ctrl + Shift + < decreases font size one step
• Ctrl + ] increases by 1 point
• Ctrl + [ decreases by 1 point

In Outlook on the web (formerly Outlook Web App), the compose toolbar includes a font size option under the formatting bar — sometimes hidden behind a "..." or "More formatting options" button depending on your screen width.

Setting a Default Font Size for All New Emails

If you find yourself manually resizing text every time you compose, setting a default saves that repeated effort.

In the Outlook desktop app:

1. Go to File → Options → Mail
2. Under the Compose messages section, click Stationery and Fonts
3. Here you'll find three separate font settings:
   • New mail messages — controls what font and size you start with when composing
   • Replying or forwarding messages — controls your text when you reply
   • Composing and reading plain text messages — applies to plain text format only

Each has its own Font button where you can set the typeface, style, size, and color independently.

This setting only affects emails you write in HTML format. If your account defaults to plain text, the plain text setting applies instead.

Changing How You Read Incoming Emails 🔍

This is a separate adjustment entirely. Outlook lets you zoom in on individual messages or change the reading pane display more broadly.

Zoom on a single message:

• Open the email, then use Ctrl + scroll wheel to zoom in or out
• Or look for the zoom slider in the bottom-right corner of the reading pane

Changing the reading pane zoom default in Outlook desktop is more limited — there's no persistent "always display at 125%" setting for incoming messages built into the standard interface. What you can do is adjust your Windows display scaling (Settings → System → Display → Scale) which increases text size across all apps, including Outlook.

In Outlook on the web, your browser controls the zoom level. Ctrl + + and Ctrl + - adjust the whole page, or you can use your browser's zoom settings to set a default zoom percentage for the Outlook web address.

Variables That Affect Which Approach Works for You

Font Size on Outlook Mobile

The Outlook app for iOS and Android doesn't have its own font size controls for composing. Instead, it inherits text size from your device's system accessibility settings:

• iPhone/iPad: Settings → Accessibility → Display & Text Size → Larger Text
• Android: Settings → Accessibility → Font size and style

These affect how Outlook's interface renders, but they don't change the font size embedded in the emails you send — that's still determined by whatever default your desktop or web client has set.

Plain Text vs. HTML Format

This distinction matters more than most people expect. HTML format supports full font customization — size, typeface, color, bold, and more. Plain text format strips all of that out. If you're composing in plain text and wondering why your font size changes aren't sticking, that's why. The recipient sees plain text rendered in their own client's default font, not yours.

You can check and change your default format in File → Options → Mail → Compose messages in this format. ✉️

Why the "Right" Size Isn't Universal

Standard body text in business email typically sits around 10–12pt, but what reads comfortably depends on the monitor resolution you're using, the display scaling your system applies, whether you're reading on a high-DPI screen, and the preferences of whoever receives your emails. A 14pt font looks generous on a standard 1080p monitor and barely noticeable on a high-resolution 4K display.

Recipients also see your email rendered through their own client — which may override or reinterpret your font choices depending on their settings, email client, and whether they've set a minimum font size in their own preferences. 🖥️

What looks right to you in the compose window may render differently for your recipient, which is one reason email design never quite behaves like a word processor.