With the start date in A1:

=IF(DAY(A1+90)=1,A1+90,DATE(YEAR(A1+90),MONTH(A1+9 0)+1,1))

Note that with a start date of 1/2/2004, adding 90 days takes you to 4/1/2004.
The above formula returns 4/1/2004 rather than 5/1/2004. If the interval must
be at least 91 days, both of the following formulas return 5/1

=IF(DAY(A1+91)=1,A1+91,DATE(YEAR(A1+91),MONTH(A1+9 1)+1,1))
=DATE(YEAR(A1+90),MONTH(A1+90)+1,1)

I tried all 3 formulas with dates from 1/1/2004 through 12/31/2004. The only
differences involved cases where (StartDate + 90) falls on the 1st of a month.

On Thu, 30 Sep 2004 10:49:04 -0700, turboalto
wrote:

I'm creating a benefits spreadsheet to help with health insurance eligibility
and COBRA notifications.

I want to write a formula that will look at the start date entered, add 90
days to it and then return a date that is the first day of the first month
following.

So if a date of 4/15/04 was entered, the formula would return 8/1/04.