I have a worksheet where columns alternate between budgeted and actual income
by month (e.g. Col A = January Budget, Col B = January Actual, Col C = Feb
Budget...).

I need to add a year to date sum, for both budget and actual, which will
need to fluctuate to accomodate the passage of time (e.g. on March 1 include
Jan & Feb, on April 1 include Jan Feb and March).

Is there a way to make SUMIF work horizontally (like an HLOOKUP)? Then I
could just add a hidden row with the date I want that column included and
make the SUMIF criteria based on the relationship between the TODAY function
and that date. Any other ideas on how to approach this?

Thank you!
Erin