After 59.5 years old, there is no penalty. Before 59.5 years old, you can take yearly equal payments out of your IRA (implies you rolled your 401k into one) without penalty. You will need to calculate a yearly payment base on age and expected mortality date. Once you start, you got to keep taking the yearly payments until you are 59.5. This is refer to as the 72t rule. For example if you have $1,000,000 in an IRA, currently are 45, and are actuarially expected to live another 40 years, you could take a 72t distribution of $25,000.
