59.5% is the change from 400 to 638
Calculation steps:
[( 638 - 400 ) ÷ 400] x 100 = 59.5%
Formula
Percentage change = [(638 - 400) / 400] x 100
Subtract the new number by the original number
638 - 400 = 238
238 ÷ 400 = 0.595
0.595 x 100 = 59.5%
Example