166.4% is the change from 250 to 666
Calculation steps:
[( 666 - 250 ) ÷ 250] x 100 = 166.4%
Formula
Percentage change = [(666 - 250) / 250] x 100
Subtract the new number by the original number
666 - 250 = 416
416 ÷ 250 = 1.664
1.664 x 100 = 166.4%
Example