Loan Calculator
:root {
–primary-blue: #004a99;
–success-green: #28a745;
–light-background: #f8f9fa;
–dark-text: #333;
–border-color: #dee2e6;
}
body {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
background-color: var(–light-background);
color: var(–dark-text);
line-height: 1.6;
margin: 0;
padding: 20px;
}
.loan-calc-container {
max-width: 800px;
margin: 30px auto;
background-color: #ffffff;
border-radius: 8px;
box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
overflow: hidden;
padding: 30px;
}
h1, h2 {
color: var(–primary-blue);
text-align: center;
margin-bottom: 20px;
}
.input-section, .result-section {
margin-bottom: 30px;
padding: 25px;
background-color: var(–light-background);
border: 1px solid var(–border-color);
border-radius: 6px;
}
.input-group {
margin-bottom: 20px;
display: flex;
flex-direction: column;
gap: 8px;
}
label {
font-weight: 600;
color: var(–primary-blue);
}
input[type="number"],
input[type="text"],
select {
padding: 12px;
border: 1px solid var(–border-color);
border-radius: 4px;
font-size: 1rem;
width: 100%;
box-sizing: border-box;
transition: border-color 0.3s ease;
}
input[type="number"]:focus,
select:focus {
outline: none;
border-color: var(–primary-blue);
box-shadow: 0 0 0 3px rgba(0, 74, 153, 0.2);
}
button {
background-color: var(–primary-blue);
color: white;
border: none;
padding: 12px 25px;
border-radius: 5px;
cursor: pointer;
font-size: 1.1rem;
font-weight: 600;
transition: background-color 0.3s ease, transform 0.2s ease;
display: block;
width: 100%;
margin-top: 10px;
}
button:hover {
background-color: #003366;
transform: translateY(-2px);
}
.result-display {
text-align: center;
margin-top: 20px;
padding: 20px;
background-color: var(–success-green);
color: white;
border-radius: 6px;
font-size: 1.8rem;
font-weight: 700;
box-shadow: 0 2px 10px rgba(40, 167, 69, 0.4);
}
.result-label {
display: block;
font-size: 1rem;
font-weight: 500;
margin-bottom: 8px;
color: rgba(255, 255, 255, 0.8);
}
.article-content {
margin-top: 40px;
padding: 30px;
background-color: #ffffff;
border: 1px solid var(–border-color);
border-radius: 6px;
}
.article-content h2 {
color: var(–dark-text);
text-align: left;
border-bottom: 2px solid var(–primary-blue);
padding-bottom: 10px;
margin-bottom: 20px;
}
.article-content p, .article-content ul, .article-content li {
margin-bottom: 15px;
}
.article-content ul {
padding-left: 20px;
}
@media (max-width: 768px) {
.loan-calc-container {
margin: 15px auto;
padding: 20px;
}
.result-display {
font-size: 1.5rem;
}
}
Loan Payment Calculator
Your Monthly Payment
Monthly Payment
$0.00
Total Interest Paid
$0.00
Total Amount Repaid
$0.00
Understanding Your Loan Payments
This loan calculator is designed to help you estimate your monthly payments for various types of loans, such as mortgages, auto loans, or personal loans. By inputting the loan amount, the annual interest rate, and the loan term in years, you can quickly see how much you can expect to pay each month. This tool is invaluable for budgeting and financial planning, allowing you to make informed decisions about borrowing.
The Math Behind the Monthly Payment
The calculation for a fixed-rate loan payment is based on the following formula, often referred to as the annuity formula:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
Where:
- M = Your total monthly payment
- P = The principal loan amount (the amount you borrow)
- i = Your monthly interest rate (annual interest rate divided by 12)
- n = The total number of payments over the loan's lifetime (loan term in years multiplied by 12)
Step-by-Step Calculation:
- Convert Annual Rate to Monthly Rate: The annual interest rate (e.g., 5%) is divided by 12 to get the monthly rate. So, for 5% annual, the monthly rate 'i' is 0.05 / 12 ≈ 0.004167.
- Calculate Total Number of Payments: The loan term in years (e.g., 30 years) is multiplied by 12 to get the total number of payments. For 30 years, 'n' is 30 * 12 = 360.
- Apply the Formula: These values (P, i, n) are then plugged into the formula to calculate 'M'.
Additional Metrics Calculated:
- Total Interest Paid: This is calculated by multiplying your total monthly payment (M) by the total number of payments (n) and then subtracting the original loan amount (P).
Total Interest = (M * n) - P. This shows you the total cost of borrowing over the life of the loan.
- Total Amount Repaid: This is simply the sum of the monthly payment multiplied by the total number of payments.
Total Repaid = M * n. It represents the total amount of money you will have paid back to the lender by the end of the loan term.
Use Cases for This Calculator:
- Mortgage Planning: Estimate your monthly mortgage payments to see if a property is affordable.
- Auto Loan Comparisons: Compare different car loan offers based on their monthly payment amounts.
- Personal Loan Assessment: Understand the cost of personal loans for various needs.
- Budgeting: Factor loan payments accurately into your monthly budget.
- Financial Literacy: Gain a better understanding of how interest rates and loan terms affect borrowing costs.
Remember, this calculator provides an estimate for fixed-rate loans. Variable-rate loans or loans with additional fees may have different payment structures. Always consult with your lender for precise loan terms and conditions.
function calculateLoan() {
var loanAmount = parseFloat(document.getElementById("loanAmount").value);
var annualInterestRate = parseFloat(document.getElementById("annualInterestRate").value);
var loanTermYears = parseFloat(document.getElementById("loanTermYears").value);
var monthlyPaymentResultElement = document.getElementById("monthlyPaymentResult");
var totalInterestResultElement = document.getElementById("totalInterestResult");
var totalRepaymentResultElement = document.getElementById("totalRepaymentResult");
// Clear previous results
monthlyPaymentResultElement.innerHTML = '
Monthly Payment$0.00′;
totalInterestResultElement.innerHTML = '
Total Interest Paid$0.00′;
totalRepaymentResultElement.innerHTML = '
Total Amount Repaid$0.00′;
// Input validation
if (isNaN(loanAmount) || loanAmount <= 0 ||
isNaN(annualInterestRate) || annualInterestRate < 0 ||
isNaN(loanTermYears) || loanTermYears <= 0) {
// Optionally display an error message, or just ensure results are cleared
return;
}
var monthlyInterestRate = annualInterestRate / 100 / 12;
var numberOfPayments = loanTermYears * 12;
var monthlyPayment = 0;
var totalInterestPaid = 0;
var totalAmountRepaid = 0;
// Handle the case where interest rate is 0%
if (monthlyInterestRate === 0) {
monthlyPayment = loanAmount / numberOfPayments;
} else {
// Standard Amortization Formula
monthlyPayment = loanAmount * (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments)) / (Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1);
}
totalAmountRepaid = monthlyPayment * numberOfPayments;
totalInterestPaid = totalAmountRepaid – loanAmount;
// Format results to two decimal places
var formattedMonthlyPayment = monthlyPayment.toFixed(2);
var formattedTotalInterestPaid = totalInterestPaid.toFixed(2);
var formattedTotalAmountRepaid = totalAmountRepaid.toFixed(2);
monthlyPaymentResultElement.innerHTML = '
Monthly Payment$' + formattedMonthlyPayment;
totalInterestResultElement.innerHTML = '
Total Interest Paid$' + formattedTotalInterestPaid;
totalRepaymentResultElement.innerHTML = '
Total Amount Repaid$' + formattedTotalAmountRepaid;
}