UDF (user defined function) replacement for Excel's DATEDIF function

[ccallisen]

Hi Rick, thank you for this UDF - it is very useful. Unfortunately I am having some challenges using it to generate 'x years y months z days'-type output in Word. Because of the way the DateDiff() function in VBA works, I find that I have to do a manual work-around to count the right number of years/months/etc if the day of the month or month of the year in the second date is before the day/month in the first date. For example, DateDiff(FirstDate, SecondDate, "m"), where FirstDate = 20/02/2002 and SecondDate = 15/08/2002 returns 6, when it should only be 5.

I've addressed this problem so that it seems to work in 99% of scenarios, but I'm still having the occasional problem where the number of years is miscounted, or where a day is dropped for some reason. The code I am using is below, and these are the results that it generates. I know this is a bit of a big one, but any assistance would be appreciated:

FirstDate	SecondDate	Result	Comments
01/07/00	30/06/04	4 yrs 0 mths 0 days	correct
30/07/11	30/06/13	2 yrs 11 mths 1 days	should be 1 yrs 11 mths 1 days
15/02/02	20/08/02	0 yrs 6 mths 6 days	correct
15/02/02	20/08/03	1 yrs 6 mths 6 days	correct
20/02/02	15/08/02	0 yrs 5 mths 27 days	correct
20/02/02	15/08/03	1 yrs 5 mths 27 days	correct
20/08/01	15/02/02	0 yrs 5 mths 27 days	correct
20/08/01	15/02/04	2 yrs 5 mths 27 days	correct
01/07/00	30/06/01	1 yrs 0 mths 0 days	correct
08/07/11	08/06/13	1 yrs 11 mths 1 days	correct
30/10/96	30/08/05	8 yrs 10 mths 1 days [td]correct
12/06/85	12/06/86	1 yrs 0 mths 1 days	correct
31/01/08	31/08/10	2 yrs 7 mths 0 days	should be 2 yrs 7 mths 1 days
31/01/08	31/08/09	1 yrs 7 mths 0 days	should be 1 yrs 7 mths 1 days
31/03/07	01/08/08	1 yrs 4 mths 2 days	correct
31/03/07	01/08/12	5 yrs 4 mths 2 days	correct
31/08/07	01/03/08	0 yrs 6 mths 2 days	correct
31/08/07	01/03/12	4 yrs 6 mths 2 days	correct