Determine exactly how much car you can afford based on your desired monthly payment and loan terms.
Maximum Vehicle Purchase Price:
$0.00
How Much Car Can I Afford?
Buying a car is one of the most significant financial decisions you will make. While many dealerships focus on the total sticker price, most budgets operate on a monthly basis. Our Car Loan Affordability Calculator flips the math: you tell us what you can afford each month, and we tell you the maximum vehicle price you should look for.
Understanding the Variables
Monthly Payment: The amount you can comfortably pay without sacrificing other financial goals.
Interest Rate: Based on your credit score. Better credit usually secures lower APRs.
Loan Term: Common terms are 60 or 72 months. While longer terms lower monthly payments, they increase the total interest paid.
Down Payment & Trade-in: These amounts directly reduce the amount you need to borrow, allowing you to buy a more expensive car for the same monthly cost.
Realistic Example: The Mid-Sized Sedan
Imagine you have $400/month budgeted for a car. You have a $3,000 down payment and a credit score that qualifies you for a 5% interest rate over 60 months. In a state with 7% sales tax:
Loan Amount Afforded: ~$21,196
Plus Down Payment: $3,000
Total Car Price: ~$22,613 (After accounting for tax)
The 20/4/10 Rule for Car Buying
Financial experts often recommend the "20/4/10" rule to ensure your vehicle doesn't become a financial burden:
20% Down: Aim to put at least 20% down to avoid being "upside down" (owing more than the car is worth) as soon as you drive off the lot.
4 Year Term: Try to limit the loan to 48 months (4 years). This keeps interest costs down and aligns with the vehicle's depreciation.
10% of Income: Your total transportation costs (loan, insurance, fuel, maintenance) should not exceed 10% of your gross monthly income.
Don't Forget the Hidden Costs
The "sticker price" isn't the final price. When using this calculator, we include an estimated Sales Tax because this is often rolled into the financing or paid upfront. Additionally, remember to budget for car insurance, which can vary significantly depending on the vehicle model and your driving history.
function calculateAffordability() {
var monthlyPayment = parseFloat(document.getElementById('monthlyPayment').value);
var annualRate = parseFloat(document.getElementById('interestRate').value);
var months = parseFloat(document.getElementById('loanTerm').value);
var downPayment = parseFloat(document.getElementById('downPayment').value) || 0;
var tradeIn = parseFloat(document.getElementById('tradeIn').value) || 0;
var taxRate = parseFloat(document.getElementById('salesTax').value) || 0;
// Validation
if (isNaN(monthlyPayment) || isNaN(annualRate) || isNaN(months) || monthlyPayment <= 0 || months <= 0) {
alert("Please enter valid numbers for payment, rate, and term.");
return;
}
// Monthly interest rate
var r = (annualRate / 100) / 12;
var loanPrincipal;
if (r === 0) {
loanPrincipal = monthlyPayment * months;
} else {
// PV = Pmt * [(1 – (1 + r)^-n) / r]
loanPrincipal = monthlyPayment * (1 – Math.pow(1 + r, -months)) / r;
}
// The loan covers the car price + tax – down payment – trade in
// Loan = ((Price * (1 + TaxRate)) – Down – Trade)
// Price = (Loan + Down + Trade) / (1 + TaxRate)
var decimalTax = taxRate / 100;
var maxVehiclePrice = (loanPrincipal + downPayment + tradeIn) / (1 + decimalTax);
// Update UI
var resultBox = document.getElementById('result-box');
var maxPriceDisplay = document.getElementById('maxPrice');
var breakdownDisplay = document.getElementById('loanBreakdown');
resultBox.style.display = 'block';
maxPriceDisplay.innerHTML = "$" + maxVehiclePrice.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
breakdownDisplay.innerHTML = "This includes a total loan amount of $" +
loanPrincipal.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}) +
" and an estimated $" +
(maxVehiclePrice * decimalTax).toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}) +
" in sales tax.";
// Smooth scroll to result
resultBox.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}