108.4% is the change from 250 to 521
Calculation steps:
[( 521 - 250 ) ÷ 250] x 100 = 108.4%
Formula
Percentage change = [(521 - 250) / 250] x 100
Subtract the new number by the original number
521 - 250 = 271
271 ÷ 250 = 1.084
1.084 x 100 = 108.4%
Example