1445% is the change from 20 to 309
Calculation steps:
[( 309 - 20 ) ÷ 20] x 100 = 1445%
Formula
Percentage change = [(309 - 20) / 20] x 100
Subtract the new number by the original number
309 - 20 = 289
289 ÷ 20 = 14.45
14.45 x 100 = 1445%
Example