How not to calculate an annual return
Your broker can help you determine what your returns have been on your investments. In the meantime, know that you can't merely divide your simple return by the number of years held because of the compounding power of money. We can use a dramatic example to illustrate why.
Building-products manufacturer Patrick Industries (PATK +1.73%) produced an average annual return of close to 100% for the five years leading up to late 2015, meaning the stock doubled on average every year for five years. If you try to calculate its annual return by dividing its simple return by five, you'd get the wrong answer. (3,100% / 5 = 620%, not 100%.) That's because returns compound — a double in year two doesn't just double the original stock value, but it also doubles the previous year's double.