221.96% is the change from 255 to 821
Calculation steps:
[( 821 - 255 ) ÷ 255] x 100 = 221.96%
Formula
Percentage change = [(821 - 255) / 255] x 100
Subtract the new number by the original number
821 - 255 = 566
566 ÷ 255 = 2.219607843137255
2.219607843137255 x 100 = 221.96%