How to Enable Dark Mode in Microsoft Outlook

If you spend eight hours a day staring at Microsoft Outlook, the stark white background of your inbox can cause significant eye strain, especially if you work in a dimly lit office or check your emails late at night. The harsh contrast of black text on a bright white background forces your eyes to work harder than necessary.

To combat this, Microsoft introduced Dark Mode across the entire Office suite. Enabling Dark Mode flips the color palette, changing the blazing white background to a soothing dark grey or black, and turning the text white. This drastically reduces glare and can even save battery life on laptops with OLED screens.

How to Enable Dark Mode in Outlook (Windows Desktop App)

The desktop version of Outlook is tied to the Microsoft Office theme settings. Changing the theme in Outlook will simultaneously apply Dark Mode to Word, Excel, and PowerPoint.

1. Open the Microsoft Outlook application on your PC.
2. Look at the very top left corner of the screen and click on File.
3. In the blue sidebar that appears on the left, look toward the bottom and click on Office Account (or just “Account” depending on your version).
4. In the middle of the screen, look for the dropdown menu labeled Office Theme.
5. Click the dropdown menu and select Black (for a true dark mode) or Dark Gray (if the pure black contrast is too intense).

The moment you select the theme, the entire interface—including your inbox list, the ribbon, and the reading pane—will instantly shift to dark mode. You do not need to restart the application.

The “Sun/Moon” Toggle Switch

When you use the “Black” theme, you might occasionally receive an email containing a complex company logo or a colored chart that is impossible to read against a black background.

Outlook provides a brilliant solution for this: the Sun/Moon toggle. Look at the top right corner of any email you are currently reading. You will see a small icon of a Sun (or a Moon). Clicking this icon instantly flips the background of only that specific email body back to white, leaving the rest of the application dark.

How to Enable Dark Mode in Outlook on the Web (Outlook.com)

If you check your email through a web browser instead of the desktop app, the process is different because it is isolated from your Windows system settings.

1. Open your web browser and log into Outlook.com or your organization’s Outlook web portal.
2. Look at the top right corner of the screen and click the Gear icon (Settings).
3. A settings panel will slide out on the right side of the screen.
4. Look for the toggle switch labeled Dark mode and switch it to the ON position.

The web interface will immediately transition to the dark theme. Just like the desktop app, the web version also includes the Sun/Moon icon inside individual emails so you can temporarily toggle the reading pane to white if necessary.

How to Enable Dark Mode in the Outlook Mobile App (iOS and Android)

The Outlook mobile app is uniquely designed to respect your phone’s system-wide settings, meaning you usually don’t have to change it manually if your phone is already in dark mode.

1. Open the Outlook app on your iPhone or Android device.
2. Tap your Profile picture (or the Home icon) in the top left corner to open the sidebar.
3. At the bottom left of the sidebar, tap the Gear icon to open Settings.
4. Scroll down the settings list and tap on Appearance (under the Preferences section).
5. You have three choices:
   • Light: Forces the app to stay white forever.
   • Dark: Forces the app into Dark Mode forever.
   • System Default (Recommended): The app will automatically switch to Dark Mode at sunset, or whenever your phone’s operating system enters dark mode.