It is a legal requirement for account holders to withdraw money from their individual retirement account when they turn 70 1/2 years old. The minimum withdrawal required is determined by dividing the account balance by the life expectancy of the account holder or the applicable distribution period.
This information can be found on the website of the Internal Revenue Service. Failure to withdraw the required distribution results in an excise tax of 50 percent. The money has to be disbursed by the year end. In the first year, however, account holders have until the following April to starting taking payments.