156.25% is the change from 320 to 820
Calculation steps:
[( 820 - 320 ) ÷ 320] x 100 = 156.25%
Formula
Percentage change = [(820 - 320) / 320] x 100
Subtract the new number by the original number
820 - 320 = 500
500 ÷ 320 = 1.5625
1.5625 x 100 = 156.25%