If you want to subtract days then you can just subtract this from a
date. For example, put a date in A1, put the number 10 in B1 and this
in C1:

=A1-B1

Format C1 as a date, and you will see that it is 10 days earlier than
your date in A1.

If you want to subtract months, then the easiest way is to multiply
the number of months by 30 and then subtract this.

Hope this helps.

Pete

On Aug 1, 7:42 pm, Alf Andersen <Alf
wrote:
I'm using excel 2003 in a large procurement project.
I know the dates when the various equipment needs to be delivered to the
sight. I also know the various delivery-, shipping- and process times given
as a number of days or months.
The project involves 100's of items and I need to be able to revise either
date or delivery times etc. and this change should then be reflected in a
changed project start date.
So how do I subtract/add a known number of days/months from a date?
All help is sincerely appreciated!