With the preponderance of financial calculators available on the Internet, it hardly seems necessary to learn how to do any investment calculations yourself.
But there's one calculation that's easy to understand and use on your own: the rule of 72. It can help you determine which financial instruments to choose to meet your investing goals. It can also help you calculate the effects of inflation on prices or your nest egg.
Read my Investopedia article, How To Double Your Money Every Six Years, to learn what the rule of 72 is and how to use it to perform calculations like these.