Amortization Schedule Calculator
body {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
background-color: #f8f9fa;
color: #333;
line-height: 1.6;
margin: 0;
padding: 20px;
}
.loan-calc-container {
max-width: 900px;
margin: 30px auto;
background-color: #ffffff;
padding: 30px;
border-radius: 8px;
box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}
h1, h2 {
color: #004a99;
text-align: center;
margin-bottom: 20px;
}
.input-section, .result-section, .article-section {
margin-bottom: 30px;
padding: 20px;
border: 1px solid #e0e0e0;
border-radius: 6px;
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.input-group {
margin-bottom: 15px;
display: flex;
flex-wrap: wrap;
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flex: 1 1 150px;
margin-right: 10px;
font-weight: bold;
color: #004a99;
text-align: right;
}
.input-group input[type="number"],
.input-group input[type="text"] {
flex: 2 1 200px;
padding: 10px 12px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 1rem;
box-sizing: border-box;
}
.input-group input[type="number"]:focus,
.input-group input[type="text"]:focus {
border-color: #004a99;
outline: none;
box-shadow: 0 0 0 2px rgba(0, 74, 153, 0.2);
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button {
display: block;
width: 100%;
padding: 12px 20px;
background-color: #004a99;
color: white;
border: none;
border-radius: 4px;
font-size: 1.1rem;
cursor: pointer;
transition: background-color 0.3s ease;
margin-top: 10px;
}
button:hover {
background-color: #003366;
}
#result {
background-color: #e7f3ff;
padding: 20px;
border-radius: 6px;
text-align: center;
font-size: 1.3rem;
font-weight: bold;
color: #004a99;
margin-top: 20px;
}
#result span {
color: #28a745;
}
.amortization-table {
width: 100%;
border-collapse: collapse;
margin-top: 20px;
font-size: 0.9rem;
}
.amortization-table th, .amortization-table td {
border: 1px solid #ddd;
padding: 8px;
text-align: right;
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.amortization-table th {
background-color: #004a99;
color: white;
font-weight: bold;
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.amortization-table tr:nth-child(even) {
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.article-section p, .article-section ul {
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.article-section ul {
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.article-section li {
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@media (max-width: 600px) {
.input-group {
flex-direction: column;
align-items: stretch;
}
.input-group label {
text-align: left;
margin-bottom: 5px;
}
.input-group input[type="number"],
.input-group input[type="text"] {
width: 100%;
}
.loan-calc-container {
padding: 20px;
}
}
Amortization Schedule Calculator
Loan Summary
Enter loan details to see the summary and schedule.
Amortization Schedule
| Payment # |
Payment Date |
Starting Balance |
Payment |
Interest Paid |
Principal Paid |
Ending Balance |
Understanding Amortization Schedules
An amortization schedule is a table that details each periodic payment on an amortizing loan (like a mortgage or auto loan). For each payment, it breaks down how much goes towards interest and how much goes towards the principal balance. It also shows the remaining balance after each payment.
How Amortization Works
Amortizing loans are structured so that each payment consists of two parts:
- Interest Payment: This is the cost of borrowing money, calculated on the outstanding principal balance for that period.
- Principal Payment: This is the portion of the payment that reduces the actual amount borrowed.
In the early stages of a loan, a larger portion of your payment goes towards interest. As the principal balance decreases, the interest portion also decreases, and a larger portion of your payment is applied to the principal. This means you pay down the loan faster over time.
The Math Behind the Schedule
The calculation involves several steps:
- Calculate the Monthly Interest Rate: Divide the annual interest rate by 12.
Monthly Rate = Annual Rate / 12
- Calculate the Total Number of Payments: Multiply the loan term in years by 12.
Total Payments = Loan Term (Years) * 12
- Calculate the Monthly Payment (P&I): This is the most complex part, using the loan payment formula:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
Where:
- M = Monthly Payment
- P = Principal Loan Amount
- i = Monthly Interest Rate
- n = Total Number of Payments
- Generate the Schedule: For each payment period:
- Interest Paid: Calculate the interest due on the outstanding balance for that month.
Interest = Remaining Balance * Monthly Interest Rate
- Principal Paid: Subtract the interest paid from the total monthly payment.
Principal = Monthly Payment – Interest Paid
- Ending Balance: Subtract the principal paid from the starting balance for that period.
Ending Balance = Starting Balance – Principal Paid
- The ending balance of one period becomes the starting balance for the next.
Use Cases for an Amortization Schedule
An amortization schedule is invaluable for:
- Budgeting: Understanding your fixed monthly loan payment and how it's allocated.
- Financial Planning: Seeing how quickly you'll build equity in a home or pay off a car loan.
- Extra Payments: Determining how extra principal payments affect the loan payoff timeline and total interest paid.
- Loan Comparison: Evaluating different loan offers by comparing their amortization impacts.
Use this calculator to generate your personalized amortization schedule and gain clarity on your loan obligations.
function calculateAmortization() {
var loanAmount = parseFloat(document.getElementById("loanAmount").value);
var annualInterestRate = parseFloat(document.getElementById("annualInterestRate").value);
var loanTermYears = parseInt(document.getElementById("loanTermYears").value);
var resultDiv = document.getElementById("result");
var tableBody = document.getElementById("amortizationTableBody");
var tableContainer = document.getElementById("amortizationTableContainer");
resultDiv.innerHTML = "";
tableBody.innerHTML = "";
tableContainer.style.display = "none";
if (isNaN(loanAmount) || isNaN(annualInterestRate) || isNaN(loanTermYears) || loanAmount <= 0 || annualInterestRate < 0 || loanTermYears 0) {
monthlyPayment = loanAmount * (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments)) / (Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1);
} else {
monthlyPayment = loanAmount / numberOfPayments; // Simple division if interest rate is 0
}
var totalInterestPaid = 0;
var currentBalance = loanAmount;
var paymentDate = new Date(); // Start date for payments
var scheduleHtml = ";
for (var i = 1; i <= numberOfPayments; i++) {
var interestPayment = currentBalance * monthlyInterestRate;
var principalPayment = monthlyPayment – interestPayment;
// Adjust last payment to ensure balance is exactly zero
if (i === numberOfPayments) {
principalPayment = currentBalance;
monthlyPayment = interestPayment + principalPayment;
}
var endingBalance = currentBalance – principalPayment;
// Format date for display (e.g., YYYY-MM-DD)
var month = paymentDate.getMonth() + 1; // getMonth() is 0-indexed
var year = paymentDate.getFullYear();
var formattedDate = year + '-' + (month < 10 ? '0' + month : month) + '-' + paymentDate.getDate();
scheduleHtml += '
';
scheduleHtml += '| ' + i + ' | ';
scheduleHtml += '' + formattedDate + ' | ';
scheduleHtml += '$' + currentBalance.toFixed(2) + ' | ';
scheduleHtml += '$' + monthlyPayment.toFixed(2) + ' | ';
scheduleHtml += '$' + interestPayment.toFixed(2) + ' | ';
scheduleHtml += '$' + principalPayment.toFixed(2) + ' | ';
scheduleHtml += '$' + endingBalance.toFixed(2) + ' | ';
scheduleHtml += '
';
totalInterestPaid += interestPayment;
currentBalance = endingBalance;
// Move to the next month for the payment date
paymentDate.setMonth(paymentDate.getMonth() + 1);
}
var totalPaymentsAmount = monthlyPayment * numberOfPayments;
var totalPrincipalPaid = loanAmount; // Should be equal to loanAmount if calculated correctly
resultDiv.innerHTML = `
Monthly Payment (P&I):
$${monthlyPayment.toFixed(2)}
Total Interest Paid:
$${totalInterestPaid.toFixed(2)}
Total Amount Paid:
$${(totalPaymentsAmount).toFixed(2)}
`;
tableBody.innerHTML = scheduleHtml;
tableContainer.style.display = "block";
}