-37.64% is the change from 821 to 512
Calculation steps:
[( 512 - 821 ) ÷ 821] x 100 = -37.64%
Formula
Percentage change = [(512 - 821) / 821] x 100
Subtract the new number by the original number
512 - 821 = -309
-309 ÷ 821 = -0.3763702801461632
-0.3763702801461632 x 100 = -37.64%
Example