83.57% is the change from 420 to 771
Calculation steps:
[( 771 - 420 ) ÷ 420] x 100 = 83.57%
Formula
Percentage change = [(771 - 420) / 420] x 100
Subtract the new number by the original number
771 - 420 = 351
351 ÷ 420 = 0.8357142857142857
0.8357142857142857 x 100 = 83.57%