3980% is the change from 20 to 816
Calculation steps:
[( 816 - 20 ) ÷ 20] x 100 = 3980%
Formula
Percentage change = [(816 - 20) / 20] x 100
Subtract the new number by the original number
816 - 20 = 796
796 ÷ 20 = 39.8
39.8 x 100 = 3980%
Example