-51.87% is the change from 831 to 400
Calculation steps:
[( 400 - 831 ) ÷ 831] x 100 = -51.87%
Formula
Percentage change = [(400 - 831) / 831] x 100
Subtract the new number by the original number
400 - 831 = -431
-431 ÷ 831 = -0.5186522262334536
-0.5186522262334536 x 100 = -51.87%