2042.5% is the change from 40 to 857
Calculation steps:
[( 857 - 40 ) ÷ 40] x 100 = 2042.5%
Formula
Percentage change = [(857 - 40) / 40] x 100
Subtract the new number by the original number
857 - 40 = 817
817 ÷ 40 = 20.425
20.425 x 100 = 2042.5%
Example