56.47% is the change from 255 to 399
Calculation steps:
[( 399 - 255 ) ÷ 255] x 100 = 56.47%
Formula
Percentage change = [(399 - 255) / 255] x 100
Subtract the new number by the original number
399 - 255 = 144
144 ÷ 255 = 0.5647058823529412
0.5647058823529412 x 100 = 56.47%