How Long Will Retirement Savings Last Calculator

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Retirement Savings Duration Calculator

Estimate how many years your nest egg will support your lifestyle.

Your Savings Will Last:

How Long Will Your Retirement Savings Last?

Planning for retirement is a balancing act between your accumulated wealth, your monthly expenses, and external factors like market performance and inflation. This calculator helps you visualize the runway of your financial independence by calculating how many years and months your current savings will last based on your spending habits.

Understanding the Calculation

This tool uses the Real Rate of Return to provide a more accurate estimate. The real rate of return is the profit made on an investment after accounting for inflation. By subtracting the inflation rate from your expected return, we can calculate your "purchasing power" over time.

Key Variables Defined:

  • Total Retirement Savings: The total sum of all your liquid assets intended for retirement (401k, IRA, Brokerage).
  • Monthly Withdrawal: The net amount you plan to take out of your accounts each month to cover living expenses.
  • Expected Annual Return: The average percentage you expect your investments to grow each year.
  • Expected Inflation: The rate at which the cost of goods and services increases, typically averaging around 2-3% historically.

Example Scenario

If you have $500,000 in savings and plan to withdraw $2,500 per month, with a 6% annual return and 3% inflation, your money would last approximately 30 years and 11 months. This assumes you are adjusting your withdrawals upward with inflation to maintain the same standard of living.

Expert Tip: If your expected return is higher than your withdrawal rate plus inflation, your money may theoretically last indefinitely. This is often referred to as "living off the interest."
function calculateRetirementDuration() { var savings = parseFloat(document.getElementById('savingsAmount').value); var monthlyWithdrawal = parseFloat(document.getElementById('monthlySpend').value); var annualReturn = parseFloat(document.getElementById('annualReturn').value) / 100; var inflation = parseFloat(document.getElementById('inflationRate').value) / 100; var display = document.getElementById('resultDisplay'); var longevityText = document.getElementById('longevityYears'); var messageText = document.getElementById('longevityMessage'); if (isNaN(savings) || isNaN(monthlyWithdrawal) || isNaN(annualReturn) || isNaN(inflation) || savings <= 0 || monthlyWithdrawal = monthlyWithdrawal) { longevityText.innerHTML = "Indefinitely"; messageText.innerHTML = "Your expected investment growth exceeds your spending, meaning your principal will likely never be depleted under these conditions."; return; } // Calculation using the annuity depletion formula // n = -ln(1 – (Pv * r) / PMT) / ln(1 + r) try { var innerBracket = 1 – (savings * r / monthlyWithdrawal); if (innerBracket <= 0) { longevityText.innerHTML = "Indefinitely"; messageText.innerHTML = "Based on these rates, your savings are growing faster than you are spending."; } else { n = -Math.log(innerBracket) / Math.log(1 + r); var totalYears = Math.floor(n / 12); var totalMonths = Math.round(n % 12); if (totalMonths === 12) { totalYears++; totalMonths = 0; } var yearLabel = totalYears === 1 ? "Year" : "Years"; var monthLabel = totalMonths === 1 ? "Month" : "Months"; longevityText.innerHTML = totalYears + " " + yearLabel + " & " + totalMonths + " " + monthLabel; messageText.innerHTML = "At a monthly spend of " + monthlyWithdrawal.toLocaleString() + ", your " + savings.toLocaleString() + " nest egg will be exhausted in " + totalYears + " years."; } } catch (e) { longevityText.innerHTML = "Calculation Error"; messageText.innerHTML = "Please check your inputs and try again."; } }

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