50% is the change from 300 to 450
Calculation steps:
[( 450 - 300 ) ÷ 300] x 100 = 50%
Formula
Percentage change = [(450 - 300) / 300] x 100
Subtract the new number by the original number
450 - 300 = 150
150 ÷ 300 = 0.5
0.5 x 100 = 50%
Example