952.5% is the change from 40 to 421
Calculation steps:
[( 421 - 40 ) ÷ 40] x 100 = 952.5%
Formula
Percentage change = [(421 - 40) / 40] x 100
Subtract the new number by the original number
421 - 40 = 381
381 ÷ 40 = 9.525
9.525 x 100 = 952.5%
Example