How to Change Your Outlook Theme (Including Dark Mode)

Outlook can look bright and white or dark and easy on the eyes late at night, and changing it takes under a minute. Where you change it depends on whether you're using new Outlook or classic Outlook, and there's one surprise in classic Outlook: the theme isn't just for Outlook. Here's how to switch, how to keep emails readable in dark mode, and how to undo it.

Change the theme in new Outlook

1. Select Settings at the top of the window.
2. Choose General, then Appearance.
3. Under Dark mode, choose Dark, Light or Use system settings.
4. Select Save.

Use system settings is the one I'd pick if your computer already switches between light and dark at different times of day: Outlook follows along automatically, so you never have to think about it again.

Change the theme in classic Outlook

1. Select File, then Office Account.
2. Under Office Theme, choose a theme such as Black.
3. Select the back arrow to return to your inbox.

Here's the catch Microsoft points out: the theme you choose in classic Outlook applies to all your Microsoft 365 desktop apps. Switch Outlook to Black and Word and Excel go black too. That's fine for most people, but worth knowing before you wonder why your spreadsheets suddenly look different.

New and classic at a glance

	New Outlook	Classic Outlook
Where	Settings, General, Appearance	File, Office Account, Office Theme
Dark option	Dark mode set to Dark	The Black theme, which includes dark mode
Affects other apps?	Just Outlook	All Microsoft 365 desktop apps

Keep emails readable in dark mode

Dark mode turns the reading pane dark too, which Microsoft says reduces eye strain. Some emails, especially designed newsletters, can look odd on a dark background. You have options:

• Brighten the reading pane for a single message using the button at the top of the reading pane.
• Switch to the original formatting with the button at the top of the reading pane.
• In new Outlook, go to the View tab and choose Light Reading Pane to keep messages light while the rest of Outlook stays dark.

Writing emails in dark mode

When you're composing, you can flip just that message between light and dark with Toggle light background or Toggle dark background on the Message toolbar. It only changes how the message looks to you while you write, which is handy for checking how an email will look to someone reading it in a light inbox.

Turn dark mode off

In new Outlook, go back to Settings, General, Appearance, choose Light or Use system settings and select Save. In classic Outlook, choose a different Office Theme under File, Office Account.

Dark mode on your phone

The Outlook mobile apps have their own appearance settings, separate from your computer. On an iPhone, Outlook can follow the phone's own light or dark setting, and you can override it in the app's settings. On Android, there's a theme option in the app's settings too. If you've set your computer to dark and your phone still looks bright, that's why: each device keeps its own choice, so set them both the way you like.

Themes and accessibility

A theme isn't just about looks. If you find bright screens tiring, or need stronger contrast to read comfortably, the dark or black options can make a real difference over a long working day. Microsoft also has guidance on using colour and contrast for accessibility across Microsoft 365, which is worth a read if the standard themes don't quite work for your eyes. Don't put up with an inbox that gives you a headache: it's a two-minute change.

Why bother with dark mode?

If you work in the evenings or spend hours in your inbox, a darker screen can feel easier on the eyes, which is exactly the reason Microsoft gives for the dark reading pane. In bright daylight, many people find the light theme sharper. There's no right answer: try each for a day and keep the one you notice less.

A note for anyone sending emails

If you send newsletters or designed emails, remember many of your readers use dark mode. Logos with transparent backgrounds and dark text can disappear on a dark screen. Test your emails in both modes before sending, and use the compose toggle above as a quick check. My re-engagement email template is a simple, text-led format that reads well in either, and my office productivity hacks cover other ways to make Outlook more comfortable to use.

My verdict

New Outlook: Settings, General, Appearance, then Dark, Light or Use system settings. Classic Outlook: File, Office Account, Office Theme, remembering it changes every Microsoft 365 desktop app. Use Light Reading Pane if emails look strange in the dark.

Frequently asked questions

How do I change the theme in Outlook?

In new Outlook, select Settings, General, Appearance and choose Dark, Light or Use system settings. In classic Outlook, use File, Office Account, Office Theme.

How do I turn on dark mode in Outlook?

In new Outlook, go to Settings, General, Appearance, choose Dark under Dark mode and select Save. In classic Outlook, choose the Black Office Theme.

Why did Word turn dark when I changed my Outlook theme?

Microsoft says the classic Outlook theme applies to all Microsoft 365 desktop apps.

How do I keep emails white in Outlook dark mode?

In new Outlook, select View, then Light Reading Pane, or brighten a single message from the button at the top of the reading pane.

How do I turn off dark mode in Outlook?

In new Outlook, choose Light or Use system settings under Settings, General, Appearance, then Save.