How to get difference in hours and minutes compared to current time.

How to get difference in hours and minutes compared to current time.

Give the followin date:
  1. 2016/11/18 21:00
I want to know what is the difference between the above date and the current date and time . 

I need the difference in hours and minutes , so it will be .... what is the difference between the above date and time and the currently date and time in hours and minutes. 

I am somehow not able to get how to calculate this :( 

Thank you.
Gautam.