Total value of IRAs, 401(k)s, and brokerage accounts.
Nominal return (e.g., 6.0% for balanced portfolio).
Average long-term US inflation (approx 2.5%).
Your Withdrawal Strategy
Recommended Safe Withdrawal Rate:0.00%
Annual Withdrawal Amount (Year 1):$0.00
Monthly Income Equivalent:$0.00
Years of Income Provided:0 Years
*This calculation assumes you deplete the principal exactly by age , adjusting withdrawals annually for inflation.
function calculateSWR() {
// Get Inputs
var currentAge = parseFloat(document.getElementById("swr_currentAge").value);
var targetAge = parseFloat(document.getElementById("swr_targetAge").value);
var portfolio = parseFloat(document.getElementById("swr_portfolio").value);
var returnRate = parseFloat(document.getElementById("swr_return").value);
var inflationRate = parseFloat(document.getElementById("swr_inflation").value);
var errorDiv = document.getElementById("swr_error");
var resultsDiv = document.getElementById("swr_results");
// Reset display
errorDiv.style.display = "none";
resultsDiv.style.display = "none";
// Validation
if (isNaN(currentAge) || isNaN(targetAge) || isNaN(portfolio) || isNaN(returnRate) || isNaN(inflationRate)) {
errorDiv.innerHTML = "Please fill in all fields with valid numbers.";
errorDiv.style.display = "block";
return;
}
if (targetAge <= currentAge) {
errorDiv.innerHTML = "Life Expectancy must be greater than Current Age.";
errorDiv.style.display = "block";
return;
}
if (portfolio <= 0) {
errorDiv.innerHTML = "Portfolio value must be greater than 0.";
errorDiv.style.display = "block";
return;
}
// Logic
var n = targetAge – currentAge; // Number of years
// Calculate Real Return: (1 + nominal) / (1 + inflation) – 1
var r = ((1 + (returnRate / 100)) / (1 + (inflationRate / 100))) – 1;
var swrDecimal;
// If real return is effectively 0, simple division
if (Math.abs(r) < 0.0000001) {
swrDecimal = 1 / n;
} else {
// Amortization Formula for Annuity: PMT = PV * [ r / (1 – (1+r)^-n) ]
// Since we want the rate (PMT/PV), we just calculate the bracketed part.
swrDecimal = r / (1 – Math.pow(1 + r, -n));
}
// Formatting Results
var swrPercent = (swrDecimal * 100).toFixed(2);
var annualAmount = portfolio * swrDecimal;
var monthlyAmount = annualAmount / 12;
// Update UI
document.getElementById("res_swr_percent").innerText = swrPercent + "%";
document.getElementById("res_annual_amount").innerText = "$" + annualAmount.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("res_monthly_amount").innerText = "$" + monthlyAmount.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("res_years").innerText = n + " Years";
document.getElementById("res_target_age_display").innerText = targetAge;
resultsDiv.style.display = "block";
}
Understanding Safe Withdrawal Rates by Age
Determining a "safe" withdrawal rate (SWR) is one of the most critical components of retirement planning in the United States. While the famous "4% Rule" (derived from the Trinity Study) suggests a 4% withdrawal rate is safe for a standard 30-year retirement, your specific age significantly alters this metric.
This Safe Withdrawal Rate by Age Calculator adjusts the math based on your life expectancy. A 65-year-old planning for 30 years needs a different rate than an 80-year-old planning for 15 years, or an early retiree at 40 planning for 55 years.
How Calculation Works: The "PMT" Approach
This tool uses an actuarial approach known as the "Capital Depletion" method. It calculates the maximum percentage of your portfolio you can withdraw in the first year—subsequently adjusted for inflation—so that your balance hits exactly zero at your Target Age.
Shorter Time Horizon: If you are older, you have fewer years to fund. This mathematically allows for a higher withdrawal rate (often 5% to 7%+).
Longer Time Horizon: If you retire early (FIRE movement), your money must last longer. This requires a lower withdrawal rate (often 3% to 3.5%) to mitigate "sequence of returns" risk.
Key Inputs for US Retirees
To get the most accurate result, consider these factors common in the US financial landscape:
1. Inflation (CPI)
The purchasing power of the dollar erodes over time. The Federal Reserve targets an inflation rate of 2%, but historical averages hover around 2.5% to 3%. This calculator adjusts your investment returns to "Real Returns" to account for this.
2. Portfolio Composition
Your "Expected Annual Return" depends on your asset allocation:
Aggressive (Mostly Stocks/S&P 500): Historically generates 8-10% nominal returns, but with higher volatility.
Why Not Just Use the 4% Rule?
The 4% rule is a rigid heuristic. As you age, sticking to 4% might result in you dying with a massive surplus of cash that you could have enjoyed. Conversely, retiring at 30 and using 4% might deplete your funds by age 70. This calculator provides a customized rate tailored to the specific duration you need your money to last.
Disclaimer: This calculator is for educational purposes only and does not constitute financial advice. It assumes a constant rate of return, whereas real markets are volatile. It is recommended to maintain a buffer or consult a fee-only financial planner for a comprehensive retirement plan.