103.52% is the change from 256 to 521
Calculation steps:
[( 521 - 256 ) ÷ 256] x 100 = 103.52%
Formula
Percentage change = [(521 - 256) / 256] x 100
Subtract the new number by the original number
521 - 256 = 265
265 ÷ 256 = 1.03515625
1.03515625 x 100 = 103.52%