257.5% is the change from 240 to 858
Calculation steps:
[( 858 - 240 ) ÷ 240] x 100 = 257.5%
Formula
Percentage change = [(858 - 240) / 240] x 100
Subtract the new number by the original number
858 - 240 = 618
618 ÷ 240 = 2.575
2.575 x 100 = 257.5%
Example