261.18% is the change from 255 to 921
Calculation steps:
[( 921 - 255 ) ÷ 255] x 100 = 261.18%
Formula
Percentage change = [(921 - 255) / 255] x 100
Subtract the new number by the original number
921 - 255 = 666
666 ÷ 255 = 2.611764705882353
2.611764705882353 x 100 = 261.18%