Try the following instead...

Assumptions:

A2:A100 contains the data

B2:B100 contains the week number

Formula:

=SUM(IF(FREQUENCY(IF($B$2:$B$100=D2,$A$2:$A$100),I F($B$2:$B$100=D2,$A$2:$
A$100)),1))

....where D2 contains the week number. Note that the formula needs to be
confirmed with CONTROL+SHIFT+ENTER, not just ENTER.

Hope this helps!

In article <6c623c86ca197@uwe, "inta251 via OfficeKB.com" <u30987@uwe
wrote:

Thanks for quick respond.
In both cases formulas count number of entrees in week 1, 2,€¦.53.
I need count days per week in Column A
Now Ill try simple. In Column A I have only dates.
Same dates entrees can be from 1 to infinity.

Sample: In this case
Date
01/08/2007
01/08/2007
01/08/2007 1st day
01/09/2007
01/09/2007
01/09/2007 2nd day
01/10/2007
01/10/2007
01/10/2007
01/10/2007
01/10/2007 3rd day
01/11/2007
01/11/2007
01/11/2007
01/11/2007 4th day
01/12/2007
01/12/2007 5th day
and so on

All this days belong to Week #2
This meet i worked 5 days in week 2.
Formula need with result 5.
Next Week #3,........53 (end of the year)
Thanks again. Igor.