Just add the two together. If A1 contains the true Excel date/time 4/5/2009
3:35 PM and you want to add 48 hours 10 minutes:

A1 = 4/5/2009 3:35 PM
B1 = 48:10

=A1+B1

Returns 4/7/2009 3:45 PM

The largest amount of time *that can be manually entered* in a cell is
9999:99:99. If you need times greater than that then you'd have to enter it
as numeric integers and then convert the hours to days + the minutes.

For example, to add 10000 hours 10 minutes:

A1 = 4/5/2009 3:35 PM
B1 = 10000
C1 = 10

=A1+B1/24+TIME(0,C1,0)

Returns 5/27/2010 7:45 AM

If you want the weekday displayed use the custom format of:

dddd m/d/yyyy h:mm AM/PM

--
Biff
Microsoft Excel MVP


"excelguy" wrote in message
...
I want to add an amount of hours to a particular day and time during that
day. For example, I want Excel to compute what time and day it would be if
I
add 6 hours to 6PM on Sunday (the first day of the week). In general, I
want
to make a formula so I can figure out what time and day it would be for
any
amount of hours I add so that I'd be able to figure out for example what
time
and day it would be a million hours and 43 minutes from Sunday at 3:35pm.
Any
Ideas?? thanks so much