This Retirement Planner Calculator helps you estimate your potential retirement nest egg and assess whether your current savings and contributions are on track to meet your desired retirement income. It takes into account your current age, when you plan to retire, your existing savings, how much you plan to save annually, and your expected investment growth and inflation rates.
How the Calculation Works:
The calculator estimates the future value of your current savings and future contributions, compounded annually. It then projects your retirement needs based on your desired annual income and the expected inflation rate.
Future Value of Current Savings:
The formula used is: FV = PV * (1 + r)^n
FV: Future Value
PV: Present Value (Current Savings)
r: Annual Investment Return Rate (as a decimal)
n: Number of years until retirement
Future Value of Annual Contributions:
This is calculated using the future value of an ordinary annuity formula: FVA = P * [((1 + r)^n - 1) / r]
FVA: Future Value of Annuity
P: Periodic Payment (Annual Contributions)
r: Annual Investment Return Rate (as a decimal)
n: Number of years until retirement
Total Projected Retirement Savings:
This is the sum of the future value of your current savings and the future value of your annual contributions.
Retirement Nest Egg Needed:
This is a simplified projection. A common rule of thumb is the "4% rule," which suggests you can safely withdraw 4% of your retirement savings each year. To estimate the total nest egg needed to support your desired annual income, we can rearrange this: Nest Egg = Desired Annual Income / Withdrawal Rate. For instance, if you want $70,000 per year and assume a 4% withdrawal rate, you'd need $70,000 / 0.04 = $1,750,000.
The calculator directly compares your projected savings against this derived nest egg target.
Inflation Adjustment:
The desired retirement income is assumed to be in today's dollars. The calculation implicitly accounts for inflation by projecting the growth of your savings at a *real* rate of return (investment return minus inflation), if you were to input a real rate. However, for simplicity in this model, we use the nominal return rate for savings growth and compare it against the nominal income need, acknowledging that the *purchasing power* of that income will be less in the future due to inflation. A more complex model would discount future income to present value.
Use Cases:
Early Planning: See how small changes in savings rate or retirement age can impact your future.
Goal Setting: Determine realistic savings targets for your desired retirement lifestyle.
Investment Strategy: Understand the importance of investment returns and how they compound over time.
Contribution Adjustments: Evaluate if increasing your annual contributions is necessary.
Disclaimer: This calculator provides an estimate for informational purposes only. It does not constitute financial advice. Actual results may vary due to market fluctuations, changes in personal circumstances, and other factors. Consult with a qualified financial advisor for personalized guidance.
function calculateRetirement() {
var currentAge = parseFloat(document.getElementById("currentAge").value);
var retirementAge = parseFloat(document.getElementById("retirementAge").value);
var currentSavings = parseFloat(document.getElementById("currentSavings").value);
var annualContributions = parseFloat(document.getElementById("annualContributions").value);
var annualReturnRate = parseFloat(document.getElementById("annualReturnRate").value) / 100; // Convert percentage to decimal
var inflationRate = parseFloat(document.getElementById("inflationRate").value) / 100; // Convert percentage to decimal
var desiredRetirementIncome = parseFloat(document.getElementById("desiredRetirementIncome").value);
var resultValueElement = document.getElementById("result-value");
var resultMessageElement = document.getElementById("result-message");
// — Input Validation —
if (isNaN(currentAge) || currentAge <= 0 ||
isNaN(retirementAge) || retirementAge <= 0 ||
isNaN(currentSavings) || currentSavings < 0 ||
isNaN(annualContributions) || annualContributions < 0 ||
isNaN(annualReturnRate) || annualReturnRate < 0 ||
isNaN(inflationRate) || inflationRate < 0 ||
isNaN(desiredRetirementIncome) || desiredRetirementIncome <= 0) {
resultValueElement.innerText = "Invalid Input";
resultMessageElement.innerText = "Please enter valid positive numbers for all fields.";
return;
}
if (retirementAge 0) {
fvAnnualContributions = annualContributions * ( (Math.pow(1 + annualReturnRate, yearsToRetirement) – 1) / annualReturnRate );
} else {
// If return rate is 0, future value is just the sum of contributions
fvAnnualContributions = annualContributions * yearsToRetirement;
}
// Total Projected Retirement Savings
var totalProjectedSavings = fvCurrentSavings + fvAnnualContributions;
// Calculate required nest egg based on desired income and 4% rule
// Assume desiredRetirementIncome is in today's dollars.
// For simplicity, we'll compare against this nominal value.
// A more sophisticated model would account for inflation's impact on future income needs.
var requiredNestEgg = desiredRetirementIncome / 0.04; // Using 4% withdrawal rate
var message = "";
if (totalProjectedSavings >= requiredNestEgg) {
message = "Congratulations! Based on these assumptions, you are projected to have enough savings for your desired retirement income.";
} else {
var shortfall = requiredNestEgg – totalProjectedSavings;
message = "Based on these assumptions, you may have a shortfall in your retirement savings. Consider increasing savings, adjusting retirement age, or revising return expectations.";
}
// Display the result
resultValueElement.innerText = "$" + totalProjectedSavings.toLocaleString(undefined, { minimumFractionDigits: 0, maximumFractionDigits: 0 });
resultMessageElement.innerText = message;
}