calculating elapsed time over a period of days

[Jerome Ranch]

I have data that I take over time (several days).
I want to calculate total elapsed time over all the days of the
experiment.

Time data may look like this

date time data elapsed time (min)
5/12/2006 09:10:00 1 0
5/12/2006 10:40:00 200 90
5/12/2006 12:30:00 etc 200
5/12/2006 15:30:00 380
5/12/2006 17:00:00 470
5/12/2006 20:45:00 695 ( I get this far with but
when a day changes, how might I calc this)
5/13/2006 07:30:00
5/13/2006 10:40:00
5/13/2006 12:30:00
5/13/2006 15:30:00
5/14/2006 10:40:00
5/14/2006 12:30:00
5/14/2006 15:30:00


Knowing elapsed hrs I can calc minutes by mutiplying hrs*24*60.
So how might I build the logic with formulas to accompish this?


Thanks
Jerry

 

[Ardus Petus]

Assuming you have column headers (such as given in your example)
In column D1, enter formula:
=(A2+B2)-(A$2+B$2)
Drag down to fill column
Format Customized [mm]

HTH