100.5% is the change from 200 to 401
Calculation steps:
[( 401 - 200 ) ÷ 200] x 100 = 100.5%
Formula
Percentage change = [(401 - 200) / 200] x 100
Subtract the new number by the original number
401 - 200 = 201
201 ÷ 200 = 1.005
1.005 x 100 = 100.5%
Example