105.25% is the change from 400 to 821
Calculation steps:
[( 821 - 400 ) ÷ 400] x 100 = 105.25%
Formula
Percentage change = [(821 - 400) / 400] x 100
Subtract the new number by the original number
821 - 400 = 421
421 ÷ 400 = 1.0525
1.0525 x 100 = 105.25%