Calculate how much you can save by refinancing your auto loan.
Your Refinance Summary
New Monthly Payment: $0.00
Monthly Savings: $0.00
Total Interest Paid (New): $0.00
Total Lifetime Savings: $0.00
How to Use the Car Loan Refinance Calculator
Refinancing a car loan involves replacing your current high-interest debt with a new loan at a lower rate or a different term. This tool helps you visualize the immediate monthly impact and the long-term interest savings.
Understanding the Results
To get an accurate calculation, you will need your current loan statement to find your remaining balance and exact months left. If your primary goal is to lower your monthly bills, focus on the "Monthly Savings" figure. If your goal is to pay off the car for the lowest possible cost, focus on the "Total Lifetime Savings."
Example Refinance Scenario
Current Loan: $20,000 balance at 8% interest with 48 months left. Monthly payment: $488.
Refinance Offer: $20,000 at 4.5% interest for 48 months.
Results: Your new payment would be approximately $456. You would save $32 per month and $1,536 in total interest over the life of the loan.
When Should You Refinance?
Refinancing is typically most beneficial if your credit score has improved since you first took out the loan, or if market interest rates have dropped significantly. Be sure to check for any prepayment penalties on your current loan or origination fees on the new loan before proceeding.
function calculateRefinance() {
var balance = parseFloat(document.getElementById('loanBalance').value);
var currentPay = parseFloat(document.getElementById('currentPayment').value);
var currentMonths = parseFloat(document.getElementById('remainingMonths').value);
var newRate = parseFloat(document.getElementById('newRate').value);
var newTerm = parseFloat(document.getElementById('newTerm').value);
// Validation
if (isNaN(balance) || isNaN(currentPay) || isNaN(currentMonths) || isNaN(newRate) || isNaN(newTerm) || balance <= 0 || newTerm <= 0) {
alert("Please enter valid positive numbers for all fields.");
return;
}
// Monthly interest rate
var monthlyRate = (newRate / 100) / 12;
// Calculate new monthly payment using amortization formula: P = (r * PV) / (1 – (1 + r)^-n)
var newPayment;
if (monthlyRate === 0) {
newPayment = balance / newTerm;
} else {
newPayment = (balance * monthlyRate) / (1 – Math.pow(1 + monthlyRate, -newTerm));
}
// Calculations
var monthlySavings = currentPay – newPayment;
var totalOldCost = currentPay * currentMonths;
var totalNewCost = newPayment * newTerm;
var totalSavings = totalOldCost – totalNewCost;
var totalInterestNew = (newPayment * newTerm) – balance;
// Display Results
document.getElementById('resNewPayment').innerText = '$' + newPayment.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resMonthlySavings').innerText = '$' + monthlySavings.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resTotalInterest').innerText = '$' + totalInterestNew.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resTotalSavings').innerText = '$' + totalSavings.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
// Color coordination for negative savings
if (totalSavings < 0) {
document.getElementById('resTotalSavings').style.color = '#dc3545';
} else {
document.getElementById('resTotalSavings').style.color = '#28a745';
}
if (monthlySavings < 0) {
document.getElementById('resMonthlySavings').style.color = '#dc3545';
} else {
document.getElementById('resMonthlySavings').style.color = '#28a745';
}
document.getElementById('resultsArea').style.display = 'block';
}