Change font size in the message you're writing

When you're composing an email in Outlook, the font size control sits in the toolbar at the top of the message window. Open a new message or reply, and look for the font size dropdown — it usually shows a number like "11" or "12" next to the font name. Click the dropdown arrow next to that number, and a list of sizes appears: 8, 9, 10, 11, 12, 14, 16, 18, 20, 22, 24, 26, 28, and 36 points.

To change the size of text you've already typed, select the text first by clicking and dragging across it, then click the font size dropdown and choose your new size. The change applies only to the selected text. If you want to change the size of text before you type it, just click the dropdown and select a size — then start typing, and all new text will use that size until you change it again.

Key Takeaways

  • The font size dropdown is in the message composition toolbar, showing a number next to the font name.
  • Select text first, then click the dropdown to change the size of text you've already written.
  • Click the dropdown before typing to set the size for new text you're about to write.
  • Outlook offers sizes from 8 to 36 points; most emails use 11 or 12 point as standard.
  • Font size changes in one message do not affect the default size for future messages unless you change your default settings.

Set a default font size for all new messages

If you want every new email you write to start with a larger or smaller font, you can change your default. In Outlook on Windows, go to File > Options > Mail > Stationery and Fonts. Under "Composing messages," click Fonts, then choose your preferred size from the dropdown next to "Font size." Click OK to save.

On Outlook for Mac, the path is different: go to Outlook > Preferences > Composing, then look for the font size setting in the message composition options. The change takes effect the next time you open a new message.

Change font size in the message you're reading

If an email you received is hard to read because the text is too small, you can zoom in on that message without changing the sender's original formatting. At the top right of the message, look for the zoom controls — usually a plus sign, a minus sign, and a percentage. Click the plus sign to make the text larger, or click the percentage to open a zoom menu and choose a specific level like 125% or 150%.

This zoom applies only to the message you're viewing right now. When you open a different email, it returns to the default zoom level. Zooming does not change the actual font size in the message — it only changes how large it appears on your screen.

Zoom settings for reading panes and lists

If you want to change the size of text in your inbox list (the list of message subjects and senders), use the zoom control in the bottom right corner of the Outlook window. This is separate from the zoom in individual messages. Adjusting this zoom makes the sender names, subject lines, and preview text larger or smaller in your inbox view.

The reading pane — the area where you read a message — also has its own zoom. If you're reading a message in the reading pane on the right side of your screen, the zoom controls at the top right of that pane adjust only that message. Zooming the inbox list does not zoom the reading pane, and vice versa.

Font size in Outlook web and mobile apps

Outlook on the web (Outlook.com or Outlook accessed through a browser) has a simpler font size control. When you compose a message, look for the font formatting toolbar. Click the font size dropdown — it may show as a number or as "Font size" — and choose from the available options. The sizes available may differ slightly from desktop Outlook.

On Outlook mobile (iPhone, iPad, or Android), font size options are limited. You can usually change the size by selecting text and tapping the formatting menu, but not all mobile versions offer a full range of sizes. If you need precise font control, compose the message on desktop Outlook instead.

Troubleshooting font size changes that don't stick

If you change the font size but it reverts to the default when you send or save the message, check whether your email account is using plain text format instead of HTML. Plain text messages do not support font formatting. To switch to HTML, go to File > Options > Mail > Compose messages, and under "Compose in this format," select HTML instead of Plain Text.

Another reason font size may not stick is if your default font settings override your message-level changes. If you set a default font size in Stationery and Fonts, that default applies to new messages. To use a different size in a single message, select the text and change it after you've started typing, rather than changing it before you begin.

Frequently Asked Questions

Why does my font size look different when the recipient opens it?

The recipient's Outlook settings, screen resolution, and zoom level affect how large the text appears to them. You control the font size you send, but not how their email client displays it. If you want to ensure readability, use 12 point or larger and avoid very small sizes.

Can I make the font size bigger in the subject line?

No. The subject line uses a fixed size that you cannot change. Font size controls apply only to the message body. If you need to emphasize something in the subject, use capital letters or punctuation instead.

Does changing font size in one message affect other messages?

No. Each message is separate. Changing the font size in one email does not change the size in other messages you've already sent or received. To change the default for all future messages, adjust your default settings in Stationery and Fonts.

What's the largest font size Outlook offers?

The largest standard size in the dropdown is 36 point. If you need larger text, select your text, right-click, and look for font options that may allow you to type a custom size larger than 36.

How do I change font size in Outlook rules or signatures?

Signatures are edited in File > Options > Mail > Signatures. When you edit a signature, the font size controls in the signature editor work the same way as in a message — select text and use the font size dropdown. Rules do not support font formatting changes.