12.5% is the change from 280 to 315
Calculation steps:
[( 315 - 280 ) ÷ 280] x 100 = 12.5%
Formula
Percentage change = [(315 - 280) / 280] x 100
Subtract the new number by the original number
315 - 280 = 35
35 ÷ 280 = 0.125
0.125 x 100 = 12.5%
Example