-20.36% is the change from 501 to 399
Calculation steps:
[( 399 - 501 ) ÷ 501] x 100 = -20.36%
Formula
Percentage change = [(399 - 501) / 501] x 100
Subtract the new number by the original number
399 - 501 = -102
-102 ÷ 501 = -0.20359281437125748
-0.20359281437125748 x 100 = -20.36%
Example