403% is the change from 100 to 503
Calculation steps:
[( 503 - 100 ) ÷ 100] x 100 = 403%
Formula
Percentage change = [(503 - 100) / 100] x 100
Subtract the new number by the original number
503 - 100 = 403
403 ÷ 100 = 4.03
4.03 x 100 = 403%
Example