0.39% is the change from 256 to 257
Calculation steps:
[( 257 - 256 ) ÷ 256] x 100 = 0.39%
Formula
Percentage change = [(257 - 256) / 256] x 100
Subtract the new number by the original number
257 - 256 = 1
1 ÷ 256 = 0.00390625
0.00390625 x 100 = 0.39%