I Need to know the % change of revenue $ from this year(TY) vs last year(LY)
with one formula.

I am using TY €“ LY / LY = % change but result is not always correct as you
can see below.

TY LY % chg
$500 $250 100.0%
-$500 -$250 100.0%
$500 -$250 -300.0%
-$500 $250 -300.0%

I have someone copy & paste many revenue numbers for TY & LY in cells. The
% change cell is a locked formula. But the result is not accurate when gains
or losses vary.

Is there one formula to get a correct % change?
as always thanks in advance!!
--
Gene