RMDs are the minimum amounts that you must withdraw from your traditional IRA each year once you reach a certain age. The purpose of RMDs is to ensure that you do not defer taxes on your retirement savings indefinitely. You must start taking RMDs when you reach age 72 (or 70 1/2 if you were born before July 1, 1949). The amount of your RMD is calculated based on your account balance and life expectancy factor, which you can find in the IRS tables. You can use IRS Form 5329 to report your RMDs and pay any additional tax or penalty if you fail to take them on time.