Maybe the dates are text instead?
You can check it with

=ISNUMBER(Tabulation!A3)

should return TRUE if it is a date

do the same for the dates in B

Or check the cells where you put the dates (C1 and E1)
and make sure they are numbers

Other things that can throw off date formulas are if the dates have times as
well

For instance

03/19/2007 10:00 AM where the condition is <= 03/19/2007 will return FALSE
since 03/19/2007 is the same as 03/19/2007 00:00 AM thus it is less than
03/19/2007 10:00 AM


Regards,

Peo Sjoblom

"j razz" wrote in message
ps.com...
=SUMPRODUCT(--(Tabulation!$A$3:$A$54=$C$1),--(Tabulation!$B$3:$B$54<=
$E$1),--(Tabulation!AV$3:AV$54))

Givens:
$A$3:$A$54 = a range of dates starting with each sunday of each week.
$B$3:$B$54 = a range of dates ending on each saturday of each week.
AV$3:AV$54 = a range of data that I am wanting the formula to look at
and post the results from.

I am having a problem with this formula. If the date manually entered
in cell $C$1 is say 3/19/2007 and the date manually entered in cell $E
$1 is say 3/24/2007 my problem is as follows: If I have an entry that
begins on 3/19/2007 it is not counted unless I change the date to the
day before. Another issue is that the ending date is not capping off
the returned data from the range AV$3:AV$54. It is as if the <=$E$1
does not exist.

Any ideas on how to fix these issues?

Thanks,

j razz