Retirement Savings Calculator
Planning for retirement is crucial, and understanding how your savings grow over time can help you make informed decisions. This calculator helps you estimate your future retirement nest egg based on your current savings, contributions, expected rate of return, and time horizon.
.calculator-container {
font-family: sans-serif;
max-width: 600px;
margin: 20px auto;
padding: 20px;
border: 1px solid #ccc;
border-radius: 8px;
background-color: #f9f9f9;
}
.calculator-container h2 {
text-align: center;
margin-bottom: 20px;
color: #333;
}
.calculator-inputs {
display: grid;
grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
gap: 15px;
margin-bottom: 20px;
}
.input-group {
display: flex;
flex-direction: column;
}
.input-group label {
margin-bottom: 5px;
font-weight: bold;
color: #555;
}
.input-group input {
padding: 10px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 16px;
}
.calculator-inputs button {
grid-column: 1 / -1;
padding: 12px 20px;
background-color: #4CAF50;
color: white;
border: none;
border-radius: 4px;
font-size: 18px;
cursor: pointer;
transition: background-color 0.3s ease;
}
.calculator-inputs button:hover {
background-color: #45a049;
}
.calculator-result {
margin-top: 25px;
padding: 15px;
border: 1px dashed #ccc;
border-radius: 4px;
background-color: #fff;
font-size: 18px;
text-align: center;
color: #333;
}
.calculator-result strong {
color: #4CAF50;
}
function calculateRetirementSavings() {
var currentSavings = parseFloat(document.getElementById("currentSavings").value);
var annualContribution = parseFloat(document.getElementById("annualContribution").value);
var yearsToRetirement = parseInt(document.getElementById("yearsToRetirement").value);
var annualInterestRate = parseFloat(document.getElementById("annualInterestRate").value) / 100; // Convert percentage to decimal
var resultElement = document.getElementById("result");
resultElement.innerHTML = ""; // Clear previous results
// Input validation
if (isNaN(currentSavings) || currentSavings < 0) {
resultElement.innerHTML = "
Please enter a valid number for Current Retirement Savings (must be non-negative).";
return;
}
if (isNaN(annualContribution) || annualContribution < 0) {
resultElement.innerHTML = "
Please enter a valid number for Annual Contribution (must be non-negative).";
return;
}
if (isNaN(yearsToRetirement) || yearsToRetirement <= 0) {
resultElement.innerHTML = "
Please enter a valid number for Years Until Retirement (must be greater than 0).";
return;
}
if (isNaN(annualInterestRate) || annualInterestRate < -1) { // Allow for negative rates but not excessively so
resultElement.innerHTML = "
Please enter a valid number for Assumed Annual Interest Rate (e.g., 7 for 7%).";
return;
}
var futureValue = currentSavings;
for (var i = 0; i < yearsToRetirement; i++) {
futureValue += annualContribution;
futureValue *= (1 + annualInterestRate);
}
// Future value of annuity formula for contributions: P * [((1 + r)^n – 1) / r]
// where P is the annual contribution, r is the annual interest rate, and n is the number of years.
// However, the iterative approach above correctly compounds each year's contribution and previous balance.
// Let's use the iterative method as it's more illustrative and directly calculates the compounded growth.
// Check if the calculated value is reasonable (e.g., not Infinity if rate is too high or years too long)
if (!isFinite(futureValue) || futureValue < 0) {
resultElement.innerHTML = "
Calculation resulted in an invalid value. Please check your inputs, especially the interest rate and years.";
return;
}
resultElement.innerHTML = "Projected Retirement Savings:
$" + futureValue.toLocaleString(undefined, { minimumFractionDigits: 2, maximumFractionDigits: 2 }) + "";
}