Use a Uniform Lifetime Table to determine the amount of the yearly required minimum distributions from your IRA if your spouse is less than 10 years younger than you or is not your sole beneficiary, advises the Internal Revenue Service. Divide the balance in the IRA as of Dec. 31 of the previous year by your life expectancy listed in the table. You must recalculate the distribution amount each year.
You must initiate required minimum distributions from your IRA when you become 70 1/2 years old or you face a penalty tax of 50 percent of the amount that should have been distributed, according to the IRS. Although you can delay the first distribution until April 1 of the following year, you must then take the second distribution by Dec. 31 of the same year. For each subsequent year, take distributions by Dec. 31. Plan administrators can assist you in calculating your distributions, but you are responsible for distributing the correct amounts. If you own more than one IRA, calculate the distribution amounts for each IRA separately, but withdraw the distributions from any of the accounts.
There are two other tables besides the Uniform Lifetime Table that IRA owners and their beneficiaries use to calculate required minimum distributions, explains the IRS. IRA owners use the Joint and Last Survivor Table if they have a spouse more than 10 years younger who is the only beneficiary. When an account owner dies, beneficiaries use the Single Life Expectancy Table to calculate distributions from inherited accounts.