20% is the change from 400 to 480
Calculation steps:
[( 480 - 400 ) ÷ 400] x 100 = 20%
Formula
Percentage change = [(480 - 400) / 400] x 100
Subtract the new number by the original number
480 - 400 = 80
80 ÷ 400 = 0.2
0.2 x 100 = 20%
Example