With Excel 2016, Microsoft has introduced a new template called Calendar Insights.
The template surfaces how much time you spend in meetings, whom you meet with the most (and whom you ignore), which part of the day you usually meet with people. You can see your calendar as a dashboard, and interact with it to drill into specific time periods, or types of meetings, you’re interested in
Open Excel and look for the Calendar Insights template (or Business Analysis Feature Tour which is the real name)
Then hit the Let’s get started button to import your calendar
You will be asked to sign-in to your Exchange mailbox (which can be hosted either on premises or on Exchange Online)
NOTE you may be asked to trust the autodiscover endpoint found
Then you should see in the Excel taskbar the template is retrieving your calendar’s data
And… you got your calendar dashboard
Now it’s up to you to drill down and analyze these results 
You can save this workbook as Excel Macro-Enabled Workbook to be able to refresh the data anytime you want.