52.34% is the change from 256 to 390
Calculation steps:
[( 390 - 256 ) ÷ 256] x 100 = 52.34%
Formula
Percentage change = [(390 - 256) / 256] x 100
Subtract the new number by the original number
390 - 256 = 134
134 ÷ 256 = 0.5234375
0.5234375 x 100 = 52.34%