I'm a developer with Cognito Forms.
This can be a bit complicated as you will have to tell the system what the date is for both the time fields, so they know that the time is on two different days. We do have an FAQ answer for a similar question.
We are calculating the total hours with the calculation, but you can adjust the calculation you can get the minutes. To do this you would still need the 4 Date/Time fields, but you would use the following calculation.
=(EndDate.AddMinutes(EndTime.Minute + (EndTime.Hour * 60)) - StartDate.AddMinutes(StartTime.Minute + (StartTime.Hour * 60))).TotalMinutes
We also have a template with all the fields set up, along with the working calculations to provide minutes, 15 minute blocks, and hours.