The Internal Revenue Service requires that you take required distributions from an IRA that you receive as the beneficiary of a decedent. This rule applies to all IRAs, including Roth IRAs. To figure the amount of the required minimum distribution (RMD), you have to figure your life expectancy using the tables in IRS Publication 590 and your account value. You can avoid penalties by simply disbursing the entire amount of the IRA within five years or, if you are the spouse of the decedent, you can treat the IRA as your own.
Figure your initial life expectancy for the purposes of taking RMDs by using the Single Life Expectancy table. If the owner of the IRA died after the required beginning date for RMDs, use the smaller of your age or the owner's age in the year after death. If the owner died before the required beginning date for RMDs, use your age. On the table, find the age in the left-hand column and your life expectancy to the right of it. For example, if you are 27, your life expectancy equals 56.2 years.
Subtract 1 for each year that has passed since your first RMD. For this example, if three years have passed, take away 3 from 56.2 to find your life expectancy for the current year equals 53.2.
Look up the value of your IRA at the close of the previous year. For example, if you want to calculate your 2014 RMD, use the value of the account on December 31, 2013.
Divide your inherited IRA value at the close of the previous year by your life expectancy for the current year to calculate the RMD. Finishing the example, if your IRA's value equals $309,000, divide $309,000 by 53.2 to find you must withdraw $5,808.27.