600% is the change from 3 to 21
Calculation steps:
[( 21 - 3 ) ÷ 3] x 100 = 600%
Formula
Percentage change = [(21 - 3) / 3] x 100
Subtract the new number by the original number
21 - 3 = 18
18 ÷ 3 = 6
6 x 100 = 600%
Example