66.41% is the change from 256 to 426
Calculation steps:
[( 426 - 256 ) ÷ 256] x 100 = 66.41%
Formula
Percentage change = [(426 - 256) / 256] x 100
Subtract the new number by the original number
426 - 256 = 170
170 ÷ 256 = 0.6640625
0.6640625 x 100 = 66.41%