49.41% is the change from 255 to 381
Calculation steps:
[( 381 - 255 ) ÷ 255] x 100 = 49.41%
Formula
Percentage change = [(381 - 255) / 255] x 100
Subtract the new number by the original number
381 - 255 = 126
126 ÷ 255 = 0.49411764705882355
0.49411764705882355 x 100 = 49.41%
Example