120% is the change from 255 to 561
Calculation steps:
[( 561 - 255 ) ÷ 255] x 100 = 120%
Formula
Percentage change = [(561 - 255) / 255] x 100
Subtract the new number by the original number
561 - 255 = 306
306 ÷ 255 = 1.2
1.2 x 100 = 120%
Example