-25.18% is the change from 830 to 621
Calculation steps:
[( 621 - 830 ) ÷ 830] x 100 = -25.18%
Formula
Percentage change = [(621 - 830) / 830] x 100
Subtract the new number by the original number
621 - 830 = -209
-209 ÷ 830 = -0.25180722891566265
-0.25180722891566265 x 100 = -25.18%