21.88% is the change from 256 to 312
Calculation steps:
[( 312 - 256 ) ÷ 256] x 100 = 21.88%
Formula
Percentage change = [(312 - 256) / 256] x 100
Subtract the new number by the original number
312 - 256 = 56
56 ÷ 256 = 0.21875
0.21875 x 100 = 21.88%