-38.54% is the change from 820 to 504
Calculation steps:
[( 504 - 820 ) ÷ 820] x 100 = -38.54%
Formula
Percentage change = [(504 - 820) / 820] x 100
Subtract the new number by the original number
504 - 820 = -316
-316 ÷ 820 = -0.3853658536585366
-0.3853658536585366 x 100 = -38.54%