With
A1: (a date/time value....eg 12/25/2007 9:30:00 AM)
B1: (number of minutes.......eg 15)

This formula converts the number of minutes
in B1 to a time value and subtracts it from A1
C1: =A1-B1/(24*60)

Format C1 as Date/Time.

Note:
To Excel each date is a whole number
(The number of days since 31-DEC-1899)
Times are fractions of a day.
Example: Noon is 0.50.......(half a day)

Since B1 is "minutes", we need to divide it by the number
of minutes in a day (24 hrs/day x 60 minutes/hour)

Is that something you can work with?
--------------------------

Regards,

Ron
Microsoft MVP (Excel)
(XL2003, Win XP)

"dst" wrote in message
...
I have a worksheet that has 1 field with the full date, e.g. 12/25/2007
09:30
(field A) and another field that has minutes, e.g. 15. (field B) I want a
formula that can tell me the new date/time if I take field A and deduct
field
B. thanks!