JMB,

Thank you for your discovery.

Looks like Excel takes "year" but just *ONE* into consideration when the second argument (month and day) is less than the first.

I took your experiment further and played with 2/1/2007 and 1/31/2009. It yields 364. Therefore, I think the leap year is taken into consideration. The following comment in Chip's writeup still holds true.

Excel will use the year of the first date......to determine whether to include 29-February in the calculation.

You wrote: "I think XL help is misleading when it says the years are ignored."

Maybe this is why DATEDIF is no longer found using F1 after version 2000. Anyone knows if DATEDIF still exists in 2007?

Epinn

"JMB" wrote in message ...
Although using Datedif on the following
2/1/2008
1/31/2010

yields 365, but would give #NUM! if Date2 was 1/31/2008 (as Chip stated). I
think XL help is misleading when it says the years are ignored - because they
are obviously not completely ignored.



"Jim Thomlinson" wrote:

Give the bottom of this a quick look see...

http://www.cpearson.com/excel/datedif.htm
--
HTH...

Jim Thomlinson


"Epinn" wrote:

My discovery on DATEDIF ("yd") and leap year

A1:A4

2/1/2007
3/1/2008
2/1/2008
3/1/2009


formula (1) =DATEDIF(A1,A2,"yd") yields 28

formula (2) =DATEDIF(A3,A4,"yd") yields 29

I understand why this is happening - the year for the first argument is used.

I find DATEDIF and "yd" and leap year "interesting," "temperamental," "confusing," ...... <g

I am curious if "yd" is used often.

Welcome comments to this and my discovery.

Epinn