excel - VBA code to show message box popup if the formula in the target column exceeds a certain value -

i found code on site particular cell

private sub worksheet_change(byval target range) if range("a1") > 0.5     msgbox "discount high" end if end sub 

but wondering if possible make work entire column rather 1 particular cell?

try event code:

private sub worksheet_calculate()     dim rr range, r range     set rr = range("a:a").cells.specialcells(xlcelltypeformulas)     each r in rr         if r.value > 0.5             msgbox "discount high"         end if     next r end sub 

edit#1:

if want restrict message single row, remove first sub , replace with:

private sub worksheet_change(byval target range)     rt = target.row     if range("a" & rt) > 0.5         msgbox "discount high"     end if end sub