creating formula to adjust per month

[Guest]

Hi , I have been trying to find a solution for this one for quite some time
now.

Basically, I need to create a formula that automatically adjusts what cells
it sums up depending on what month you enter in to a specific cell.

So if A1=January , then my target cell equal, lets say sum(j6:j6)
while if A1 changes to A1 = February, then my target cell sums up (j6:k6)
(adds one cell to the right)
where J5 and K5 are the list of months.

I think it might be a combination of vlookup and maybe some if functions,
appreciate anyones help if you can crack it for me.

 

[Guest]

This assumes that A1 contains a date.

=sum(offset(j6,0,0,month(A1),1))

If A1 contains JUST a month name, then

=sum(offset(j6,0,0,month(datevalue(a1&"1, 2006")),1))

 

[Ardus Petus]

Target cell formula:
=SUM(OFFSET(J6,,,,MATCH(A1,J5:U5,0)))

HTH