Outlook has built-in color themes you can switch between in seconds

You can change how Outlook looks by switching its color theme. Outlook offers a light theme (white background), a dark theme (dark background), and a system default option that matches your computer's settings. The steps differ slightly depending on whether you use Outlook on Windows, Mac, or the web version, but each takes less than a minute.

The color change affects the entire Outlook window — the ribbon, sidebar, message list, and reading pane all shift together. This is different from changing the color of individual elements like your signature or message text, which requires different steps.

Key Takeaways

  • Windows Outlook users find the theme option in File > Options > General, under the "Personalization" section.
  • Mac Outlook users go to Outlook > Preferences > General and select their preferred appearance.
  • Outlook on the web (Outlook.com) has theme options in Settings > Display, accessible from the gear icon.
  • The dark theme reduces eye strain in low-light environments and uses less battery power on some devices.
  • Your theme choice syncs across devices if you use the same Microsoft account, so you only need to change it once.

How to change the theme in Outlook on Windows

Open Outlook and click the File tab in the top left corner. From the menu that appears, select Options at the bottom of the left sidebar.

In the Outlook Options window, click General in the left list. Look for the section labeled Personalization. You will see a dropdown menu next to "Office Theme" with three options: Colorful (light theme with colored accents), Dark Gray (dark theme), or White (plain light theme). Select the one you want and click OK at the bottom right. Outlook will apply the change immediately.

If you do not see the Personalization section, make sure you are in the General settings and not another category. Some older versions of Outlook may label this section differently or place it under a different menu, but the File > Options path remains the same.

How to change the theme in Outlook on Mac

Click Outlook in the menu bar at the top of the screen, then select Preferences. In the Preferences window, click General.

Scroll down to find the Appearance section. You will see options for Light, Dark, or Use system setting. Choose your preference and close the Preferences window. The theme will update right away.

The "Use system setting" option is useful if you want Outlook to match whatever theme your Mac is set to. If your Mac switches between light and dark automatically based on time of day, Outlook will do the same.

How to change the theme in Outlook on the web

Log into your Outlook account at Outlook.com. Click the gear icon in the top right corner of the screen, then select View all Outlook settings.

In the settings panel, click Display in the left menu. Under the Theme section, you will see options like Light, Dark, or Use system setting. Select the theme you want and the change will save automatically. You do not need to click a save button.

If you only see a simple gear icon without a dropdown menu, click it once and look for a "Settings" option. Some accounts show a slightly different menu layout, but the Display settings are always accessible from the main settings area.

What each theme does and when to use it

Light theme (Colorful or White) shows a bright background with dark text. This is easier to read in bright environments and matches the appearance of printed documents. Most offices and daytime users prefer the light theme.

Dark theme (Dark Gray) shows a dark background with light text. It reduces glare when you are working in dim lighting and can reduce eye strain during evening use. Dark theme also uses slightly less battery power on laptops, though the difference is small on most modern devices.

System setting automatically matches whatever your computer or phone is set to. If your Windows PC or Mac switches between light and dark based on time of day, Outlook will switch with it. This is the most convenient option if you like your operating system to handle the choice for you.

Changing text color and signature colors separately

The theme option changes the entire Outlook window, but you can also change the color of individual messages and signatures. To change the color of text in a message you are composing, highlight the text, click the arrow next to the font color button in the ribbon (it looks like an "A" with a colored line underneath), and pick a new color.

To change your signature colors, go to File > Options > Mail (Windows) or Outlook > Preferences > Signatures (Mac), find your signature in the list, click Edit, and format the text the same way you would in a message. These changes affect only that specific signature or message, not the entire Outlook interface.

Troubleshooting theme changes that do not appear

If you change the theme but Outlook still looks the same, close Outlook completely and open it again. Sometimes the change does not display until you restart the application. On Windows, use File > Exit to close Outlook fully, not just minimize it.

If you are using Outlook on the web and the theme does not change, clear your browser cache and refresh the page. Press Ctrl+Shift+Delete (Windows) or Command+Shift+Delete (Mac) to open your browser's cache clearing menu, select "All time" or "Everything", and click Clear. Then go back to Outlook.com and try changing the theme again.

If you have multiple Microsoft accounts, make sure you are signed into the account whose settings you want to change. Theme preferences are tied to your account, so switching accounts will show that account's theme choice instead.

Frequently Asked Questions

Will changing the theme affect how my emails look to other people?

No. The theme only changes how Outlook looks on your screen. When you send an email, the recipient sees it in their own Outlook theme or email client. Your choice of dark or light theme does not change the actual email content or how it appears to others.

Can I use dark theme for Outlook but light theme for other Microsoft apps?

Yes. Each Microsoft app has its own theme setting. You can set Outlook to dark, Word to light, and Excel to dark independently. The theme you choose in Outlook does not affect Teams, Word, Excel, or any other application.

Does dark theme actually save battery power?

On devices with OLED screens (some newer laptops and phones), dark theme uses slightly less battery because dark pixels require less power. On regular LCD screens, the difference is negligible. If battery life is your main concern, closing other apps and lowering screen brightness will have a much bigger impact.

What if I want to change the color of just the sidebar or ribbon?

The theme option changes the entire Outlook window as one unit — you cannot customize individual sections separately. Your only option is to choose one of the three built-in themes. If you need more customization, you would need to use a third-party Outlook add-in, though these are not officially supported by Microsoft.

Why does my Outlook theme keep changing back?

If your theme resets after you close Outlook, your changes may not have saved properly. Make sure you click OK (Windows) or close the Preferences window (Mac) after selecting your theme. If you are using Outlook on the web, wait a few seconds after selecting a theme to make sure it saves before closing the browser tab.