27.5% is the change from 320 to 408
Calculation steps:
[( 408 - 320 ) ÷ 320] x 100 = 27.5%
Formula
Percentage change = [(408 - 320) / 320] x 100
Subtract the new number by the original number
408 - 320 = 88
88 ÷ 320 = 0.275
0.275 x 100 = 27.5%
Example