Look in Help to learn about SUMIF
or try SUMPRODUCT, see
http://www.xldynamic.com/source/xld.SUMPRODUCT.html
http://mcgimpsey.com/excel/formulae/doubleneg.html

The come back if more help needed
--
Bernard V Liengme
www.stfx.ca/people/bliengme
remove caps from email

"prgmme" wrote in message
...
I have a spreadsheet that has MANY values. One column provies the size of
a
file, and another corresponding column provides the date the file was
created
(month, day, year -- and some have times). What kind of formula/macro can
I
create that will sum the sizes of the files that correspond to certain
dates?
For Example:
COLUMN A COLUMN B
34 Jul 20, 2004
2009 Jul 20, 2004
3 Aug 11, 2005
20006 Feb 3, 2006 11:15
23 Feb 3, 2006 11:15