Using formula to find out a Date 90 prior to a particular date

[Vinod]

I am trying to use a formula for finding out a date 90 days before a
particular date.
I used the formula =DATE(2009,9,25-I80) for finding a date that is 90
days before 25/9/2009.
My problem is that I have a column B with the dates get changed on each
entry and and in other column I want to get a date before 90 days.
I mean how to use the formula with the dates getting changed on each entry?
Hope you can help me out.
If req I can send you the file.

Regards
Vinod

 

[Per Jessen]

Hi Vinrod

With your date in B2, this will do it:

=B2-DAY(90)

Regards,
Per

 

[David Biddulph]

Are you sure you mean that, Per?
DAY(90) is 30, as the number 90 is Excel's representation of 30 March 1900.

Don't you just want =B2-90 ?