25% is the change from 256 to 320
Calculation steps:
[( 320 - 256 ) ÷ 256] x 100 = 25%
Formula
Percentage change = [(320 - 256) / 256] x 100
Subtract the new number by the original number
320 - 256 = 64
64 ÷ 256 = 0.25
0.25 x 100 = 25%
Example