Calculate times compared to deadlines (and over midnight) in Excel

I’m trying to build a worksheet in Excel which will compare an actual time to a deadline and then calculate the difference in time and whether the actual time is early or late. To complicate it either of the times could cross over midnight. For example; an 11:45pm deadline with a 12:05am actual, or a 12:05am deadline with an actual time of 11:45pm. Any help with formula suggestions would be appreciated.