3130% is the change from 20 to 646
Calculation steps:
[( 646 - 20 ) ÷ 20] x 100 = 3130%
Formula
Percentage change = [(646 - 20) / 20] x 100
Subtract the new number by the original number
646 - 20 = 626
626 ÷ 20 = 31.3
31.3 x 100 = 3130%
Example