How Are RMDs Calculated?
RMDs are calculated by dividing your traditional IRA or retirement plan account balance by a life expectancy factor specified in IRS tables. Your account balance is usually calculated as of December 31 of the year preceding the calendar year for which the distribution is required to be made.
Example(s): You have a traditional IRA. Your 70th birthday is November 1 of year one, and you therefore reach age 70½ in year two. Because you turn 70½ in year two, you must take an RMD for year two from your IRA. This distribution (your first RMD) must be taken no later than April 1 of year three. In calculating this RMD, you must use the total value of your IRA as of December 31 of year one.
Caution: When calculating the RMD amount for your second distribution year, you base the calculation on the IRA or plan balance as of December 31 of the first distribution year (the year you reached age 70½) regardless of whether or not you waited until April 1 of the following year to take your first required distribution.