A Look at Systematic Withdrawals This calculator may help you estimate how long funds may last given regular withdrawals. You are viewing this website at a small screen resolution which doesn't support calculators. Click here to view this calculator. Have A Question About This Topic? Name Email Address Message Thank you! Oops! Related Content Taxable vs. Tax-Deferred Savings Use this calculator to compare the future value of investments with different tax consequences. What Is My Life Expectancy? Estimate how many years you may need retirement assets or how long to provide income to a surviving spouse or children. Required Reading: The Economic Report of the President The Economic Report of the President can help identify the forces driving — or dragging — the economy.