1200% is the change from 40 to 520
Calculation steps:
[( 520 - 40 ) ÷ 40] x 100 = 1200%
Formula
Percentage change = [(520 - 40) / 40] x 100
Subtract the new number by the original number
520 - 40 = 480
480 ÷ 40 = 12
12 x 100 = 1200%
Example