How does Total Time in Case Resolution is calculated?

You might have seen the popup dialog of Resolve Case when you click on Resolve Case as below:

So, someone asked me from where the locked Total Time is calculated in the System.

I didn’t know the prompt answer for this. So, had to go through some basics and it was worth a finding to clear my concepts.

Total Time = Duration of all the Completed Activities related to Case.

Hence when I created a Task with Duration 30 minutes and marked it complete the Total Time populated that value i.e. 30 minutes.

So to conclude if I had added another Activity and marked it completed then that Duration would have summed up and shown in the Total Time field when we attempt to resolve the case.

Hope this helps.