Occasionally, Outlook may change its scaling to adjust to the size of your laptop's or desktop's screen, which will make Outlook Desktop app's interface look abnormally too big or too small.
Here's how to adjust this:
- You can adjust the percentage slider (at the bottom right) until it looks right.
(Usually 100% should look fine)
If that did not resolve the issue, you may have the wrong Windows scaling for your computer's screen. Check out our article on that: https://helpdesk.uww.umass.edu/hc/en-us/articles/360048208952-Icons-and-Fonts-Look-Too-Big-or-Too-Small-in-Windows-10