Add 90 to the cell that has the date.

If Cell A1 has the date of 10/15/1979 the following formula in cell B1 will
produce the date of 1/13/1980

=A1+90

Hope this helps...
--
Kevin Backmann


"Felicity" wrote:

I have a row of different date when people joined a study. I need to
calculate the exact date three months afterwards. How do I create a formular,
so I don't have to calculate it separately for each different person(given
that thye joined on different dates?