edate and yearfrac functions not tallying

[slymeat]

I seem to be getting differing results fromt he use of Yearfrac and edate
functions:

Example (all dates in mm/dd/yy format):

I have used the yearfrac function to calculate the difference in years
between two dates

Cell A4 contains First Date: 31/03/05
Cell D10 contains 2nd Date: 23/06/09

Cell C18 contains formula: Yearfrac(A4,D10,3) - Result is 4.23
I then want to add value in Cell C21 (1.5) to 4.23 and calculate the date:

=EDATE(A4,((C18+C21)*12))

Result is 30/11/2010

However, I also have a different cell containing the function:
=EDATE(D10,C21*12)

I get a different result: 23/12/2010

Can anybody tell me why the results are different or am I missing something
blindingly obvious?

 

[Ron Rosenfeld]

Can anybody tell me why the results are different or am I missing something
blindingly obvious?

From HELP for EDATE:

"If months is not an integer, it is truncated."

So your EDATE formula result will always be the same day of the month as your
starting date (with adjustments made for those days (e.g. 29,30,31) that may
not exist in the result.


--ron