I just used 8 cells to test (need not see the need for column B)
This array formula (use CTRL+SHIFT+ENTER to compete it)
=MAX(IF(YEAR(A1:A8)=2008,A1:A8)) gives the MAX date when year is 2008
Similarly =MIN(IF(YEAR(A1:A8)=2008,A1:A8)) will give MIN value
Subtract the two for range
Or combine the two as
=MAX(IF(YEAR(A1:A8)=2008,A1:A8)) - MIN(IF(YEAR(A1:A8)=2008,A1:A8))
to get answer in one step
If you get #VALUE! you forgot CTRL+SHIFT+ENTER

With 2008, 2009 etc in B1....use
=MAX(IF(YEAR($A$1:$A$8)=B1,$A$1:$A$8)) -
MIN(IF(YEAR($A$1:$A$8)=B1,$A$1:$A$8))
copy down to do all years

--
Bernard V Liengme
Microsoft Excel MVP
www.stfx.ca/people/bliengme
remove caps from email

"DoooWhat" wrote in message
...
I need to find the difference between the maximum and minimum values
of several different groups. I have the following data:

A B
1 1/1/2008 2008
2 1/15/2008 2008
3 1/31/2008 2008
4 4/1/2009 2009
5 4/21/2009 2009
6 7/1/2010 2010
7 7/14/2010 2010
8 7/26/2010 2010

I want to know what the range of dates is for each year. For example,
in analyzing 2008, I want a formula that will produce a value of 30.
For 2009, it should be 20. For 2010, it should be 25.

My list will be very large and will not necessarily be in the right
order. I tried to use a combination of "min", "max", and
"sumproduct", but I couldn't get it to work. This was what I came up
with.

=SUMPRODUCT((A1:A500=MIN(A1:A500))*(A1:A500<=MAX( A1:A500))*(B1:B500="2008"))

Any help would be very much appreciated.

Kevin