-95.24% is the change from 420 to 20
Calculation steps:
[( 20 - 420 ) ÷ 420] x 100 = -95.24%
Formula
Percentage change = [(20 - 420) / 420] x 100
Subtract the new number by the original number
20 - 420 = -400
-400 ÷ 420 = -0.9523809523809523
-0.9523809523809523 x 100 = -95.24%
Example