50% is the change from 128 to 192
Calculation steps:
[( 192 - 128 ) ÷ 128] x 100 = 50%
Formula
Percentage change = [(192 - 128) / 128] x 100
Subtract the new number by the original number
192 - 128 = 64
64 ÷ 128 = 0.5
0.5 x 100 = 50%
Example