Actually, I should have been more specific. What I need is a function like:

?GetTimeSpan({09/15/2000},{03/16/1999})

Returns

1.4673454

Where I am getting caught up I guess is determining the number of days in a year.

I know I am wrong so far from comparing my results with the textbook results for the same range. For example, my method (#days/365.25) gives

9.5711 years

and the book shows

9.5816 years

trouble is, I am fairly sure the 'book' uses a method called 30/360, I just don't know what that method is.

Thanks for your input.