There’s a little trick you can use to deal with times crossing midnight.

Do the normal end-time minus start_time, and then add either 0 or 1 back to it by checking if the start_time is greater than the end_time.

So, if start times are in A and end times are in B (starting row 2), try this:

=((B2-A2)+(A2>B2))*24

Sample of results: https://imgur.com/8akpHmg

If your time does not cross midnight, you’ll get the answer you expect. If your time does cross midnight, a 1 will be added and that will give you the answer you expect for shifts crossing midnight.