My Retirement Savings Estimate how long your retirement savings may last using various monthly cash flow rates. You are viewing this website at a small screen resolution which doesn't support calculators. Click here to view this calculator. Share | Have A Question About This Topic? Name Email Address Message Thank you! Oops! Related Content 18 Years Worth of Days The average retirement lasts for 18 years. Are you prepared to fill that many days? How Will Working Affect Social Security Benefits? Knowing the rules may help you decide when to start benefits. Retirement Plan Distributions There are a number of ways to withdraw money from a qualified retirement plan.