Open the email or calendar item you want to view
Hold down Ctrl and scroll the mouse wheel down
Use the zoom slider in the bottom-right corner of the message window and move it left
Click Zoom in the ribbon, then choose a smaller percentage
In Outlook on the web, press Ctrl and minus (-) to zoom out
In Outlook on Mac, press Command and minus (-) to zoom out
Reset zoom by pressing Ctrl and 0 on Windows or Command and 0 on Mac