217.9% is the change from 257 to 817
Calculation steps:
[( 817 - 257 ) ÷ 257] x 100 = 217.9%
Formula
Percentage change = [(817 - 257) / 257] x 100
Subtract the new number by the original number
817 - 257 = 560
560 ÷ 257 = 2.178988326848249
2.178988326848249 x 100 = 217.9%