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, with many lasting even longer. Will you fill your post-retirement days with purpose? What Is a Roth 401(k)? Roth 401(k) plans combine features of traditional 401(k) plans with those of a Roth IRA. A Look at Systematic Withdrawals This calculator may help you estimate how long funds may last given regular withdrawals.