660% is the change from 40 to 304
Calculation steps:
[( 304 - 40 ) ÷ 40] x 100 = 660%
Formula
Percentage change = [(304 - 40) / 40] x 100
Subtract the new number by the original number
304 - 40 = 264
264 ÷ 40 = 6.6
6.6 x 100 = 660%
Example