If base date is in A1, 20 months before base date is:

=date(year(a1),month(a1)-20,day(a1))

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Regards,
Fred


"Rob" wrote in message
...
Given a base date such as 10/1/2006, how do you return a date knowing the
number of months previous to the base date? Using this for a project plan
and want to return the value for A-20 where A is the base date and 20 is the
number of months before the base date.
Thanks for your help.