How do you work out percentage profit?

Basically, percent profit is:

(selling price - cost) / cost = decimal equivalent of percent profit

Ex. If selling price was 4 dollars, and the cost was only 2 dollar, the percent profit is:

( 4 - 2 ) / 2 = 2/2 = 1.0

To convert the resulting decimal equivalent of the percent to an indicated percentage then multiply the value (here 1.0) by 100, or move the decimal point two places rightward.

1.0 = 100% The percentage profit was 100%