This calculator helps you calculate how many hours between two days, for example, between Monday 8 a.m and Wednesday, 6 p.m. If you enter day and time for each of the two time points, it will show you how many hours (and minutes, if you wish) between these. In my example, there will be 58 hours from Monday 8 a.m to Wednesday 6 p.m. It also shows the opposite for convenience - how many hours from Wednesday 6 p.m to next Monday 8 a.m. Of course, since the week has 168 hours in total, the opposite number will be 168 - 58 = 110 hours.
While I've already created a similar calculator - Time Span Calculator, it lacks a day selector, so the one below is a little bit more versatile.