-32.42% is the change from 256 to 173
Calculation steps:
[( 173 - 256 ) ÷ 256] x 100 = -32.42%
Formula
Percentage change = [(173 - 256) / 256] x 100
Subtract the new number by the original number
173 - 256 = -83
-83 ÷ 256 = -0.32421875
-0.32421875 x 100 = -32.42%