-78.82% is the change from 255 to 54
Calculation steps:
[( 54 - 255 ) ÷ 255] x 100 = -78.82%
Formula
Percentage change = [(54 - 255) / 255] x 100
Subtract the new number by the original number
54 - 255 = -201
-201 ÷ 255 = -0.788235294117647
-0.788235294117647 x 100 = -78.82%
Example