207.41% is the change from 270 to 830
Calculation steps:
[( 830 - 270 ) ÷ 270] x 100 = 207.41%
Formula
Percentage change = [(830 - 270) / 270] x 100
Subtract the new number by the original number
830 - 270 = 560
560 ÷ 270 = 2.074074074074074
2.074074074074074 x 100 = 207.41%