Time calculations and additional 24 hour days

[Guest]

I am tring to calculate the amount of time passed over several days. I have
the start time on one day and the end time several days later. The dates are
stored in a seperate column from the times. I can calculate the time and I
can calculate the days passed. The format for the date returns a number
(either 2 for days or 48 for hours) but the time is in 00:00 format.
I need the total amount of time in either 00:00 or (0.00 prefered)

 

[Guest]

If you multiply a time value by 24 and format the result as a number (rather
than a time), you'll get the number of hours.

 

[Peo Sjoblom]

Use custom format [h]:mm