56.86% is the change from 255 to 400
Calculation steps:
[( 400 - 255 ) ÷ 255] x 100 = 56.86%
Formula
Percentage change = [(400 - 255) / 255] x 100
Subtract the new number by the original number
400 - 255 = 145
145 ÷ 255 = 0.5686274509803921
0.5686274509803921 x 100 = 56.86%