The number of years you wish to analyze. This can be any number from one to one hundred.

This is the annually compounded rate of return you expect from your investments before taxes. The actual rate of return is largely dependent on the type of investments you select. For example, from December 1999 to December 2009, the average annual compounded rate of return for the S&P 500 was -0.6%, including reinvestment of dividends. From January 1970 to December 2009, the average annual compounded rate of return for the S&P 500, including reinvestment of dividends, was approximately 10.1% (source: www.standardandpoors.com). Since 1970, the highest 12-month return was 61% (June 1982 through June 1983). The lowest 12-month return was -43% (March 2008 to March 2009). Savings accounts at a bank may pay as little as 1% or less but carry significantly lower risk of loss of principal balances.

It is important to remember that these scenarios are hypothetical and that future rates of return can't be predicted with certainty and that investments that pay higher rates of return are generally subject to higher risk and volatility. The actual rate of return on investments can vary widely over time, especially for long-term investments. This includes the potential loss of principal on your investment. It is not possible to invest directly in an index and the compounded rate of return noted above does not reflect sales charges and other fees that funds and/or investment companies may charge.

Interest on an investment's interest, plus previous interest. The more frequently this occurs, the sooner your accumulated interest will generate additional interest. You should check with your financial institution to find out how often interest is being compounded on your particular investment.

Total you currently have invested that should be included in this analysis.

What you expect for the average long-term inflation rate. A common measure of inflation in the U.S. is the Consumer Price Index (CPI), which has a long-term average of 3.1% annually, from 1925 through 2009. The CPI for 2009 was -1.0%, as reported by the Minneapolis Federal Reserve.

The amount you will contribute each year to your investments. If you check the box to adjust this amount for inflation, your annual investment will increase each year by the inflation rate.

The percentage of your investment return you will pay in taxes. Your taxes are assumed to be payable annually, at the end of the year.

Total after-tax return if your investment profit is compounded annually.

Total after-tax return if your investment profit is simple interest with no compounding.

Total you have invested. This includes your initial investment and all periodic investments.