259.77% is the change from 256 to 921
Calculation steps:
[( 921 - 256 ) ÷ 256] x 100 = 259.77%
Formula
Percentage change = [(921 - 256) / 256] x 100
Subtract the new number by the original number
921 - 256 = 665
665 ÷ 256 = 2.59765625
2.59765625 x 100 = 259.77%