307.2% is the change from 125 to 509
Calculation steps:
[( 509 - 125 ) ÷ 125] x 100 = 307.2%
Formula
Percentage change = [(509 - 125) / 125] x 100
Subtract the new number by the original number
509 - 125 = 384
384 ÷ 125 = 3.072
3.072 x 100 = 307.2%
Example