Car Loan Payment Calculator
.calculator-container {
font-family: Arial, sans-serif;
border: 1px solid #ccc;
padding: 20px;
border-radius: 8px;
max-width: 500px;
margin: 20px auto;
background-color: #f9f9f9;
}
.calculator-inputs {
margin-bottom: 20px;
}
.input-group {
margin-bottom: 15px;
display: flex;
align-items: center;
justify-content: space-between;
}
.input-group label {
margin-right: 10px;
flex-basis: 50%;
}
.input-group input {
padding: 8px;
border: 1px solid #ccc;
border-radius: 4px;
width: 50%;
box-sizing: border-box; /* Include padding and border in the element's total width and height */
}
button {
background-color: #007bff;
color: white;
padding: 10px 15px;
border: none;
border-radius: 4px;
cursor: pointer;
font-size: 16px;
width: 100%;
}
button:hover {
background-color: #0056b3;
}
.calculator-result {
margin-top: 20px;
padding: 15px;
background-color: #e9ecef;
border: 1px solid #ced4da;
border-radius: 4px;
font-size: 1.1em;
text-align: center;
font-weight: bold;
}
function calculateCarPayment() {
var carPrice = parseFloat(document.getElementById("carPrice").value);
var downPayment = parseFloat(document.getElementById("downPayment").value);
var loanTermYears = parseInt(document.getElementById("loanTerm").value);
var annualInterestRate = parseFloat(document.getElementById("interestRate").value);
var resultElement = document.getElementById("result");
if (isNaN(carPrice) || isNaN(downPayment) || isNaN(loanTermYears) || isNaN(annualInterestRate)) {
resultElement.innerHTML = "Please enter valid numbers for all fields.";
return;
}
if (carPrice <= 0 || downPayment < 0 || loanTermYears <= 0 || annualInterestRate < 0) {
resultElement.innerHTML = "Please enter positive values for price, term, and rate. Down payment can be zero.";
return;
}
var loanAmount = carPrice – downPayment;
if (loanAmount <= 0) {
resultElement.innerHTML = "The loan amount is $0 or less. No loan payment needed.";
return;
}
var monthlyInterestRate = (annualInterestRate / 100) / 12;
var numberOfPayments = loanTermYears * 12;
var monthlyPayment;
if (monthlyInterestRate === 0) {
monthlyPayment = loanAmount / numberOfPayments;
} else {
monthlyPayment = loanAmount * (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments)) / (Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1);
}
if (isNaN(monthlyPayment) || !isFinite(monthlyPayment)) {
resultElement.innerHTML = "Calculation error. Please check your inputs.";
return;
}
resultElement.innerHTML = "Your estimated monthly car payment is: $" + monthlyPayment.toFixed(2);
}
Understanding how to calculate your monthly car payment is crucial when budgeting for a new or used vehicle. This calculator helps you estimate your monthly loan repayment based on the car's price, your down payment, the loan term (in years), and the annual interest rate.
How the Car Loan Payment Calculator Works
The formula used is the standard annuity payment formula:
$M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]$
Where:
- M = Your total monthly mortgage payment
- P = The principal loan amount (Car Price – Down Payment)
- i = Your monthly interest rate (Annual Interest Rate / 12)
- n = The total number of payments over the loan's lifetime (Loan Term in Years * 12)
If the interest rate is 0%, the calculation simplifies to:
$M = P / n$
The calculator first determines the total loan amount by subtracting your down payment from the car's price. It then converts the annual interest rate to a monthly rate and the loan term in years to the total number of monthly payments. Finally, it plugs these values into the formula to compute your estimated monthly payment.
Example Calculation
Let's say you want to buy a car priced at $28,000. You plan to make a down payment of $6,000. You've secured a loan for 5 years (60 months) with an annual interest rate of 7.5%.
- Car Price: $28,000
- Down Payment: $6,000
- Loan Amount (P): $28,000 – $6,000 = $22,000
- Loan Term: 5 years
- Number of Payments (n): 5 years * 12 months/year = 60 months
- Annual Interest Rate: 7.5%
- Monthly Interest Rate (i): 7.5% / 12 = 0.625% or 0.00625
Using the formula:
$M = 22000 [ 0.00625(1 + 0.00625)^60 ] / [ (1 + 0.00625)^60 – 1]$
$M = 22000 [ 0.00625(1.00625)^60 ] / [ (1.00625)^60 – 1]$
$M = 22000 [ 0.00625(1.45329) ] / [ 1.45329 – 1]$
$M = 22000 [ 0.009083 ] / [ 0.45329 ]$
$M = 22000 * 0.020038$
$M ≈ $440.84
This means your estimated monthly car payment for this loan would be approximately $440.84. Remember that this calculation doesn't include potential additional costs like taxes, registration fees, or comprehensive insurance, which are often rolled into the loan or paid separately.