The problem I'm having is that I can't get either VLOOKUP or INDEX-MATCH queries to work if the cell I'm having it function use to reference the data is a calculation.

ie:

=INDEX(Model!$B$2:$B$269,MATCH(J11,Model!$A$2:$A$269,FALSE),1)

where

J11 = (F18+F19)/F19 [note: F18 and F19 are entered values]

The moment I change J11 to a value (say 1.136), the lookups work. Is there anyway to get around this?

Thanks!