102.5% is the change from 320 to 648
Calculation steps:
[( 648 - 320 ) ÷ 320] x 100 = 102.5%
Formula
Percentage change = [(648 - 320) / 320] x 100
Subtract the new number by the original number
648 - 320 = 328
328 ÷ 320 = 1.025
1.025 x 100 = 102.5%
Example