-88.24% is the change from 255 to 30
Calculation steps:
[( 30 - 255 ) ÷ 255] x 100 = -88.24%
Formula
Percentage change = [(30 - 255) / 255] x 100
Subtract the new number by the original number
30 - 255 = -225
-225 ÷ 255 = -0.8823529411764706
-0.8823529411764706 x 100 = -88.24%