.calc-header { background-color: #1a73e8; color: white; padding: 25px; text-align: center; }
.calc-header h2 { margin: 0; font-size: 28px; }
.calc-container { padding: 30px; display: flex; flex-wrap: wrap; gap: 20px; }
.calc-input-group { flex: 1 1 300px; }
.calc-field { margin-bottom: 20px; }
.calc-field label { display: block; font-weight: 600; margin-bottom: 8px; font-size: 14px; color: #555; }
.calc-field input, .calc-field select { width: 100%; padding: 12px; border: 1px solid #ccc; border-radius: 4px; box-sizing: border-box; font-size: 16px; }
.calc-button { background-color: #1a73e8; color: white; border: none; padding: 15px 30px; font-size: 18px; font-weight: bold; border-radius: 4px; cursor: pointer; width: 100%; transition: background 0.3s; }
.calc-button:hover { background-color: #1557b0; }
.calc-result-area { flex: 1 1 300px; background-color: #f8f9fa; padding: 25px; border-radius: 8px; border: 1px solid #e0e0e0; }
.result-title { font-size: 18px; font-weight: bold; margin-bottom: 15px; border-bottom: 2px solid #1a73e8; padding-bottom: 5px; }
.result-value { font-size: 32px; font-weight: 800; color: #1a73e8; margin: 10px 0; }
.result-detail { font-size: 14px; margin-bottom: 10px; display: flex; justify-content: space-between; }
.article-section { padding: 30px; border-top: 1px solid #eee; background-color: #fff; }
.article-section h3 { color: #1a73e8; margin-top: 25px; }
.article-section p { margin-bottom: 15px; }
.example-box { background: #eef4ff; padding: 15px; border-left: 4px solid #1a73e8; margin: 20px 0; }
@media (max-width: 600px) { .calc-container { padding: 15px; } }
function calculateCarAffordability() {
var monthlyBudget = parseFloat(document.getElementById('desiredPayment').value);
var downPayment = parseFloat(document.getElementById('downPayment').value) || 0;
var tradeInValue = parseFloat(document.getElementById('tradeIn').value) || 0;
var months = parseInt(document.getElementById('loanTerm').value);
var annualRate = parseFloat(document.getElementById('interestRate').value);
var taxRate = parseFloat(document.getElementById('salesTax').value) / 100;
if (isNaN(monthlyBudget) || monthlyBudget <= 0) {
alert("Please enter a valid monthly payment amount.");
return;
}
var monthlyRate = (annualRate / 100) / 12;
// Formula to calculate Loan Principal (L) from Monthly Payment (P)
// L = P * [ (1+r)^n – 1 ] / [ r * (1+r)^n ]
var loanAmount = 0;
if (monthlyRate === 0) {
loanAmount = monthlyBudget * months;
} else {
var powerTerm = Math.pow(1 + monthlyRate, months);
loanAmount = monthlyBudget * (powerTerm – 1) / (monthlyRate * powerTerm);
}
// Total available for car (before tax adjustments)
// CarPrice + (CarPrice – TradeIn) * TaxRate = Loan + DownPayment + TradeIn
// var Subtotal = Loan + DownPayment + TradeIn
// CarPrice * (1 + TaxRate) – TradeIn * TaxRate = Subtotal
// CarPrice = (Subtotal + TradeIn * TaxRate) / (1 + TaxRate)
var totalAvailableSubtotal = loanAmount + downPayment + tradeInValue;
var maxCarPrice = (totalAvailableSubtotal + (tradeInValue * taxRate)) / (1 + taxRate);
// If Trade-in is higher than car price (rare), the tax logic shifts, but for a purchase calc:
if (maxCarPrice < tradeInValue) {
maxCarPrice = totalAvailableSubtotal / (1 + taxRate);
}
var totalTax = (maxCarPrice – tradeInValue) * taxRate;
if (totalTax < 0) totalTax = 0;
var totalInterest = (monthlyBudget * months) – loanAmount;
// Update UI
document.getElementById('affordabilityResult').innerText = '$' + maxCarPrice.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resLoanAmount').innerText = '$' + loanAmount.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resInterest').innerText = '$' + totalInterest.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resTax').innerText = '$' + totalTax.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resOutOfPocket').innerText = '$' + downPayment.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
// Visual feedback
var resultCard = document.getElementById('resultCard');
resultCard.style.backgroundColor = '#e7f3ff';
setTimeout(function() {
resultCard.style.backgroundColor = '#f8f9fa';
}, 500);
}
// Initialize on load
window.onload = function() {
calculateCarAffordability();
};
Car Loan Affordability Calculator
36 months (3 years)
48 months (4 years)
60 months (5 years)
72 months (6 years)
84 months (7 years)
Estimated Purchase Power
$0.00
This is the maximum sticker price you should look for based on your monthly budget.
Total Loan Amount:
$0.00
Total Interest Paid:
$0.00
Estimated Sales Tax:
$0.00
Total Out-of-Pocket:
$0.00
How to Use the Car Affordability Calculator
Buying a car is one of the most significant financial decisions you'll make. Most experts suggest looking at your monthly budget first rather than the total sticker price. Our Car Loan Affordability Calculator helps you reverse-engineer your car shopping by starting with what you can actually afford to pay each month.
Realistic Example: If you can afford $450 per month, have $2,000 cash, and a trade-in worth $3,000, with a 60-month loan at 6% interest and 7% sales tax, you can afford a car with a sticker price of approximately $25,480.
Key Factors in Determining Car Affordability
To get the most accurate result, you need to understand the variables involved:
- Monthly Payment: Financial experts recommend the "20/4/10 rule": Put 20% down, limit the loan to 4 years (48 months), and keep total transportation costs (including insurance) under 10% of your gross income.
- The Down Payment: The more you pay upfront, the less you borrow. This directly reduces your interest charges over the life of the loan.
- Loan Term: While a 72 or 84-month loan makes your monthly payment lower, you will pay significantly more in interest and risk being "upside down" (owing more than the car is worth).
- Interest Rate (APR): This is determined by your credit score. A higher score earns a lower rate, which significantly increases your purchasing power.
Hidden Costs to Consider
Remember that the "sticker price" isn't the final cost. Our calculator accounts for sales tax, but don't forget to budget for:
- Registration and Dealer Fees: These can add $500 to $1,500 to the total cost.
- Insurance: Newer, more expensive cars often come with higher insurance premiums.
- Maintenance: Factor in an additional $50-$100 per month for tires, oil changes, and repairs.
Frequently Asked Questions
What is a good interest rate? Currently, "good" rates range from 4% to 7% for new cars and 6% to 10% for used cars, depending on your credit score.
Should I trade in my old car? Trading in is convenient and often provides a tax credit (in many states, you only pay sales tax on the difference between the new car and the trade-in). However, selling privately usually nets a higher price.