Sum column based on variable start and variable end months

Based on your sample data, here's my attempt...

=IFERROR(SUM(OFFSET($C$1,MATCH($L$2,$C$2:$C$12,0),MATCH(O1,$D$1:$I$1,0),MATCH($L$4,$C$2:$C$12,0)-MATCH($L$2,$C$2:$C$12,0)+1)),"")

its much easier if you put in a real date say first of each month and format as mmm then excel can use the values
=SUMPRODUCT(($C$2:$C$20>=$L$2)*($C$2:$C$20<=eomonth($L$4,0)),D$2:D$20) you can probaby do this with sumifs but im not on my 2007 pc at the moment

and my aattenpt, I changed your "months" to dates, and then used this, copied across and down - see attached...
=SUMIFS(OFFSET($C$1,1,MATCH(O$1,$D$1:$I$1,0),COUNT(D:D),1),$C$2:$C$12,">="&$L$2,$C$2:$C$12,"<="&$L$4)

whats all the offset about? 2 solutions with offset have i missed something obvious?

Originally Posted by martindwilson

its much easier if you put in a real date say first of each month and format as mmm then excel can use the values

As Martin so wisely points out, here is another attempt without OFFSET and just a slight change to column C.

=SUMIFS(INDEX($D$2:$I$12,,MATCH(O$1,$D$1:$I$1,0)),$C$2:$C$12,">="&$L$2,$C$2:$C$12,"<="&$L$4)

You are very welcome Steve and thanks for the feedback.

If that takes care of your original question, please select Thread Tools from the menu link above and mark this thread as SOLVED. Thanks.

Happy to help Steve and thanks for the feedback