100% is the change from 410 to 820
Calculation steps:
[( 820 - 410 ) ÷ 410] x 100 = 100%
Formula
Percentage change = [(820 - 410) / 410] x 100
Subtract the new number by the original number
820 - 410 = 410
410 ÷ 410 = 1
1 x 100 = 100%
Example