1428.57% is the change from 21 to 321
Calculation steps:
[( 321 - 21 ) ÷ 21] x 100 = 1428.57%
Formula
Percentage change = [(321 - 21) / 21] x 100
Subtract the new number by the original number
321 - 21 = 300
300 ÷ 21 = 14.285714285714286
14.285714285714286 x 100 = 1428.57%