Managed to do this with one formula IF IsNull([Green Sign]) THEN IF [Value]>[Amber High] THEN 'Red' ELSEIF [Value]<=[Amber Low] THEN 'Green' ELSE 'Amber' ENDIF ELSE IF [Value]>[Amber High] THEN 'Green' ELSEIF Value<=[Amber Low] THEN 'Red' ELSE 'Amber' ENDIF ENDIF