6.25% is the change from 320 to 340
Calculation steps:
[( 340 - 320 ) ÷ 320] x 100 = 6.25%
Formula
Percentage change = [(340 - 320) / 320] x 100
Subtract the new number by the original number
340 - 320 = 20
20 ÷ 320 = 0.0625
0.0625 x 100 = 6.25%
Example