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? Split Annuity Strategy Here's one strategy that combines two different annuities to generate income and rebuild principal. Annuity Comparison This calculator compares a hypothetical fixed annuity with an account where the interest is taxed each year.