There's no sure answer to this question. How much your $1,000 will be worth depends on the types of securities you purchase and their performance. As an example, $1,000 with a return of 7% over 20 years would equal $3,870, but that doesn’t include the cost of taxes or management fees. (7% is a reasonable assumption based on historical market growth. Between the years of 1950-2009, the stock market grew on average by 7% per year.) When it comes to investment advice, there's a very good reason you often hear “past performance does not equal future results.” It's because past performance absolutely does not equal future results. But if you're disciplined, your risk is minimized through a highly diversified portfolio, and if fees are kept low, you might be very happy with what your $1,000 grows into in the long term.