Hi shg.

thanks.

on adding it to the sheet I get an error, also the C5:e5 should be B5:d5

also the formula you suggest doesn't change the last part:

IF x in C5 then E2 / 1000*B9*C18, if x in D5 then E2 / 1000*B9*D18, if x in B5 then E2 / 1000*B9*B18, in no x then error because user MUST select.

I'm sorry I cannot suggest something myself.. but as I wrote.. I have no idea..
I can see the logic in what you're suggesting, but not what's missing.