If you have a tax-deferred IRA, such as a traditional IRA, the federal government forces you to take out money from your IRA in the year you turn 70 1/2. As an encouragement to make sure you withdraw the money you are supposed to, the IRS charges a 50 percent penalty if you do not take out the required amount. Part of calculating the minimum required distribution depends on your life expectancy. To figure your life expectancy you have to use the life expectancy tables in IRS Publication 590.
Use the Uniform Lifetime Table unless an exception applies. If your spouse is at least 10 years younger than you, you can use the Joint and Last Survivor Table. If you inherited your IRA, use the Single Life Expectancy Table.
Figure your age and, if using the the Joint and Survivor Table, the age of your spouse for the year that you want to calculate your IRA withdrawal by using your age in whole years at the end of the calendar year. For example, if in 2013 you turn 82 on November 15, you are 82 for the purposes of your 2013 minimum withdrawal.
Locate your age in the left-hand column of the table and find your life expectancy in the cell next to your age. For example, if you are 82 and using the Uniform Lifetime Table, your life expectancy equals 17.1 years. If using the Joint and Last Survivor Table, also locate your spouse's age across the top. Find your life expectancy where the row of your age and column of the age of your spouse meet. For example, if you are 82 and your spouse is 71, your life expectancy equals 17.7 years.