Definitions

Annual contribution: The amount you will contribute to your ROTH IRA each year. This calculator assumes that you make your contribution at the beginning of each year. In 2007, the maximum annual IRA contribution is $4,000 per individual. It is important to note that this is the maximum total contributed to all of your IRA accounts. This maximum will increase to $5,000 in 2008. Beginning in 2009, the contribution limit will adjust annually for inflation in $500 increments.
In 2008, if you are 50 or older, you can make an additional "catch-up" contribution of $1,000. In order to qualify for the "catch-up" contribution, you must turn 50 by the end of the year in which you are making the contribution.
It is important to note that Roth IRA contributions are limited for higher incomes. If your income falls in a "phase-out" range you are allowed only a prorated Roth IRA contribution. If your income exceeds the phase-out range, you do not qualify for any Roth IRA contribution. For the purposes of this calculator, we assume that your income does not limit your ability to contribute to a Roth IRA. The table below summarizes the income "phase-out" ranges for Roth IRAs.

Tax filing status	2008 Income Phase-Out Range
Married filing jointly or Head of household	$159,000 to $169,000
Single	$101,000 to $116,000
Married filing separately	$0 to $10,000

Expected rate of return: The annual rate of return for your IRA. This calculator assumes that your return is compounded annually and your contributions are made at the beginning of each year. The actual rate of return is largely dependent on the type of investments you select. From January 1970 to December 2007, the average compounded rate of return for the S&P 500, including reinvestment of dividends, was approximately 11.4% per year (source: www.standardandpoors.com). During this period, the highest 12-month return was 61%, and the lowest was -39%. Savings accounts at a bank pay as little as 1% or less.
It is important to remember that future rates of return can't be predicted with certainty and that investments that pay higher rates of return are 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 additional sales charges and fees that funds may charge.
Current age: Your current age.
Age of retirement: Age you wish to retire. This calculator assumes that the year you retire, you do not make any contributions to your IRA. So if you retire at age 65, your last contribution is assumed to have happened when you were actually 64.
Marginal tax rate: The marginal tax rate you expect to pay on your taxable investments.
Roth total at retirement: Total value in your Roth IRA at your retirement.
Total taxable savings: The total amount you would have accumulated by retirement in a taxable savings account.