2008 is a Leap year, so you are getting 1461 days divided by 365 days

"slymeat" wrote:

I am using the yearfrac function to calculate the difference between dates

If I use the first date as 31/03/2005 and the 2nd date as 31/03/2009 and use
the yearfrac function, the result is 4.0027397260274

Why is it not 4.00 even?