97.28% is the change from 257 to 507
Calculation steps:
[( 507 - 257 ) ÷ 257] x 100 = 97.28%
Formula
Percentage change = [(507 - 257) / 257] x 100
Subtract the new number by the original number
507 - 257 = 250
250 ÷ 257 = 0.9727626459143969
0.9727626459143969 x 100 = 97.28%