=TEXT(INT(A2-A1),"#")&" Days "&TEXT(24*(MOD(A2-A1,1)),"#")&" hrs."

this formula outputs the total number of days, and rounds the remaining
hours (18 hrs instead of 17 hrs 48 minutes).

You might be having trouble with the way you are inputing your dates. If
you format them to general you should get numbers like this.
38734.675
38742.41667
This is the actual serial number for the dates you specified. If they stay
in date format, that means the cells are actually text strings and not dates
(as far as excel is concerned). You might need to switch the day and month,
and then change the format to
dd/mm/yyyy hh:mm
to get them to show how you want.

"TBA" wrote:

I have tried a number of the responses posted- sorry i can't seem to get it
right!
I want to calculate the number of days and hours between two date time values
e.g.

cell A1 start: 17/01/2006 16:12
cell A2 finish: 25/01/2006 10:00
cell A3 answer: 7 days 18 hrs

and is it possible to leave cells A1 and A2 in dd:mm:yy hh:mm format rather
than 'general'?

thanks for your help-