Online Loan Amortization Schedule Calculator
function calculateAmortization() {
var loanAmount = parseFloat(document.getElementById("loanAmount").value);
var interestRate = parseFloat(document.getElementById("interestRate").value);
var loanTerm = parseFloat(document.getElementById("loanTerm").value);
var resultDiv = document.getElementById("amortizationResult");
resultDiv.innerHTML = "; // Clear previous results
if (isNaN(loanAmount) || isNaN(interestRate) || isNaN(loanTerm) || loanAmount <= 0 || interestRate < 0 || loanTerm <= 0) {
resultDiv.innerHTML = 'Please enter valid positive numbers for all fields.';
return;
}
var monthlyInterestRate = (interestRate / 100) / 12;
var numberOfPayments = loanTerm * 12;
// Calculate monthly payment using the formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
var monthlyPayment = loanAmount * (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments)) / (Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1);
if (isNaN(monthlyPayment) || !isFinite(monthlyPayment)) {
resultDiv.innerHTML = 'Could not calculate monthly payment. Please check your inputs.';
return;
}
var amortizationTableHTML = '
Amortization Schedule
';
amortizationTableHTML += '
';
amortizationTableHTML += '| Month | Payment | Principal | Interest | Remaining Balance |
|---|
';
amortizationTableHTML += '';
var remainingBalance = loanAmount;
var totalInterestPaid = 0;
for (var i = 1; i <= numberOfPayments; i++) {
var interestPayment = remainingBalance * monthlyInterestRate;
var principalPayment = monthlyPayment – interestPayment;
remainingBalance -= principalPayment;
totalInterestPaid += interestPayment;
// Handle potential floating point inaccuracies for the last payment
if (i === numberOfPayments) {
principalPayment = remainingBalance + principalPayment; // Ensure balance becomes zero
interestPayment = monthlyPayment – principalPayment;
remainingBalance = 0;
}
// Ensure remaining balance doesn't go slightly negative due to rounding
if (remainingBalance < 0 && i === numberOfPayments) {
remainingBalance = 0;
}
amortizationTableHTML += '';
amortizationTableHTML += '| ' + i + ' | ';
amortizationTableHTML += '$' + monthlyPayment.toFixed(2) + ' | ';
amortizationTableHTML += '$' + principalPayment.toFixed(2) + ' | ';
amortizationTableHTML += '$' + interestPayment.toFixed(2) + ' | ';
amortizationTableHTML += '$' + remainingBalance.toFixed(2) + ' | ';
amortizationTableHTML += '
';
}
amortizationTableHTML += '
';
amortizationTableHTML += '
';
amortizationTableHTML += 'Estimated Monthly Payment: $' + monthlyPayment.toFixed(2) + ";
amortizationTableHTML += 'Total Principal Paid: $' + loanAmount.toFixed(2) + ";
amortizationTableHTML += 'Total Interest Paid: $' + totalInterestPaid.toFixed(2) + ";
amortizationTableHTML += 'Total Amount Paid: $' + (loanAmount + totalInterestPaid).toFixed(2) + ";
amortizationTableHTML += '
';
resultDiv.innerHTML = amortizationTableHTML;
}
.calculator-wrapper {
font-family: Arial, sans-serif;
max-width: 800px;
margin: 20px auto;
padding: 20px;
border: 1px solid #e0e0e0;
border-radius: 8px;
background-color: #f9f9f9;
}
.calculator-title {
text-align: center;
color: #333;
margin-bottom: 25px;
}
.calculator-form {
display: grid;
grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
gap: 15px;
margin-bottom: 25px;
}
.form-group {
display: flex;
flex-direction: column;
}
.form-group label {
margin-bottom: 5px;
font-weight: bold;
color: #555;
}
.form-group input[type="number"] {
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 1rem;
}
.calculator-form button {
grid-column: 1 / -1; /* Span across all columns */
padding: 12px 20px;
background-color: #007bff;
color: white;
border: none;
border-radius: 4px;
font-size: 1.1rem;
cursor: pointer;
transition: background-color 0.3s ease;
}
.calculator-form button:hover {
background-color: #0056b3;
}
.calculator-result {
margin-top: 20px;
overflow-x: auto; /* For tables that might be too wide */
}
.table-title {
text-align: center;
color: #333;
margin-bottom: 15px;
}
.amortization-table {
width: 100%;
border-collapse: collapse;
margin-bottom: 20px;
background-color: #fff;
}
.amortization-table th,
.amortization-table td {
border: 1px solid #ddd;
padding: 10px;
text-align: right;
}
.amortization-table th {
background-color: #f2f2f2;
color: #333;
font-weight: bold;
text-align: center;
}
.amortization-table tbody tr:nth-child(even) {
background-color: #f9f9f9;
}
.summary-results {
margin-top: 15px;
padding: 15px;
border: 1px dashed #ccc;
border-radius: 5px;
background-color: #fff;
}
.summary-results p {
margin: 8px 0;
color: #333;
}
.error-message {
color: #dc3545;
font-weight: bold;
text-align: center;
}
Understanding Loan Amortization Schedules
A loan amortization schedule is a table that breaks down the periodic payments (usually monthly) for a loan. Each row in the schedule shows how much of the payment goes towards the principal (the original amount borrowed) and how much goes towards the interest, along with the remaining balance of the loan after each payment. Understanding this schedule is crucial for borrowers to see how their debt decreases over time and how much interest they will ultimately pay.
Key Components of an Amortization Schedule:
- Loan Amount (Principal): The initial sum of money borrowed.
- Interest Rate: The annual percentage charged by the lender for borrowing money. This is converted to a monthly rate for the calculation.
- Loan Term: The total duration of the loan, typically expressed in years or months.
- Monthly Payment: The fixed amount paid by the borrower each month. This payment typically covers both interest and principal.
- Interest Paid: The portion of each monthly payment that covers the interest accrued on the outstanding balance.
- Principal Paid: The portion of each monthly payment that reduces the outstanding loan balance.
- Remaining Balance: The amount of the loan that still needs to be repaid after a specific payment has been made.
How Amortization Works:
In the early stages of a loan, a larger portion of your monthly payment goes towards interest because the outstanding principal balance is highest. As you continue to make payments, the principal balance decreases, which in turn reduces the amount of interest accrued each month. Consequently, a larger portion of your subsequent payments is allocated to reducing the principal, accelerating the payoff of your loan.
The Formula Behind Monthly Payments:
The monthly payment (M) is calculated using the following formula:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
Where:
- M = Monthly Payment
- P = Principal Loan Amount
- i = Monthly Interest Rate (Annual Rate / 12)
- n = Total Number of Payments (Loan Term in Years * 12)
Example Scenario:
Let's say you take out a personal loan of $20,000 with an annual interest rate of 5% over a term of 5 years.
- Loan Amount (P): $20,000
- Annual Interest Rate: 5%
- Monthly Interest Rate (i): 0.05 / 12 = 0.004167
- Loan Term: 5 years
- Number of Payments (n): 5 * 12 = 60
Using the formula, the estimated monthly payment would be approximately $377.42.
The amortization schedule generated by our calculator will show you, month by month, how this $377.42 payment is split between interest and principal, and how the remaining balance of your $20,000 loan decreases until it reaches zero after 60 payments. You will also see the total interest paid over the life of the loan.
Benefits of Using an Amortization Calculator:
- Planning: Helps in budgeting and understanding the total cost of a loan.
- Comparison: Allows you to compare different loan offers by seeing how various interest rates and terms affect your payments and total interest paid.
- Accelerated Payments: You can use the schedule to see the impact of making extra principal payments, which can significantly reduce the loan term and total interest.
Our Loan Amortization Schedule Calculator provides a clear, detailed breakdown to help you manage your finances effectively.