Purchasing a vehicle is a significant financial decision, and understanding the terms of your auto loan is crucial. This calculator is designed to help you estimate your monthly payments for an auto loan from Becu (Boeing Employees' Credit Union), allowing you to budget more effectively.
The calculation is based on the standard auto loan amortization formula. Even though this calculator provides an estimate, actual loan offers from Becu may vary based on your creditworthiness, current market rates, and specific loan product terms.
How the Calculator Works (The Math Behind It)
The monthly payment (M) for an auto loan is calculated using the following formula:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
Where:
P = Principal loan amount (the total amount you borrow).
i = Monthly interest rate (Annual interest rate divided by 12 and then by 100). For example, a 6% annual rate is 0.06 / 12 = 0.005 monthly.
n = Total number of payments (Loan term in years multiplied by 12, or directly in months).
This formula calculates the fixed monthly payment required to fully amortize the loan over its term.
Key Factors Influencing Your Becu Auto Loan Payment:
Loan Amount (Principal): The higher the amount you borrow, the higher your monthly payments will be.
Annual Interest Rate: A lower interest rate means less interest paid over the life of the loan and typically lower monthly payments. Becu offers competitive rates, but they are influenced by market conditions and your credit history.
Loan Term (Months): A longer loan term will result in lower monthly payments, but you will pay more interest overall. A shorter term means higher monthly payments but less interest paid in the long run.
How to Use This Calculator:
1. Enter the Loan Amount: Input the total price of the vehicle you intend to purchase, minus any down payment you plan to make.
2. Set the Annual Interest Rate: Input the estimated annual interest rate. You can use the slider or type in the value. Remember that actual rates can vary.
3. Choose the Loan Term: Select the desired loan duration in months using the slider or by typing the number. Consider the balance between lower monthly payments and total interest paid.
4. Click "Calculate Monthly Payment": The calculator will display your estimated monthly payment.
Use this tool as a starting point for your car buying journey with Becu. It's recommended to visit the official Becu website or speak with a loan officer for personalized pre-approval and the most accurate loan terms.
function updateSliderValue(sliderId, valueId, unit = ") {
var slider = document.getElementById(sliderId);
var valueDisplay = document.getElementById(valueId);
var numericInput = document.getElementById(sliderId + 'Numeric');
var value = parseFloat(slider.value);
valueDisplay.textContent = value + unit;
if (numericInput) {
numericInput.value = value;
}
}
function updateNumericInput(inputId, sliderId, unit = ") {
var numericInput = document.getElementById(inputId);
var slider = document.getElementById(sliderId);
var valueDisplay = document.getElementById(sliderId + 'Value');
var value = parseFloat(numericInput.value);
// Clamp value to slider min/max
var min = parseFloat(slider.min);
var max = parseFloat(slider.max);
if (value max) value = max;
numericInput.value = value; // Update input to clamped value
slider.value = value;
valueDisplay.textContent = value + unit;
}
function calculateAutoLoan() {
var loanAmount = parseFloat(document.getElementById("loanAmount").value);
var annualInterestRate = parseFloat(document.getElementById("interestRate").value);
var loanTermMonths = parseFloat(document.getElementById("loanTerm").value);
var monthlyPaymentElement = document.getElementById("monthlyPayment");
// Basic validation
if (isNaN(loanAmount) || isNaN(annualInterestRate) || isNaN(loanTermMonths) ||
loanAmount <= 0 || annualInterestRate < 0 || loanTermMonths 0) {
// M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
var numerator = monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments);
var denominator = Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1;
monthlyPayment = loanAmount * (numerator / denominator);
} else {
// If interest rate is 0, payment is just principal divided by term
monthlyPayment = loanAmount / numberOfPayments;
}
if (isNaN(monthlyPayment) || !isFinite(monthlyPayment)) {
monthlyPaymentElement.textContent = "Calculation Error";
} else {
monthlyPaymentElement.textContent = "$" + monthlyPayment.toFixed(2);
}
}
// Initial setup and event listeners for sliders
document.addEventListener('DOMContentLoaded', function() {
// Update initial slider display values
updateSliderValue('interestRate', 'interestRateValue', '%');
updateSliderValue('loanTerm', 'loanTermValue', ' months');
// Add listeners to update display when slider changes
document.getElementById('interestRate').addEventListener('input', function() {
updateSliderValue('interestRate', 'interestRateValue', '%');
// Update numeric input for sync
updateNumericInput('interestRateNumeric', 'interestRate', '%');
});
document.getElementById('loanTerm').addEventListener('input', function() {
updateSliderValue('loanTerm', 'loanTermValue', ' months');
// Update numeric input for sync
updateNumericInput('loanTermNumeric', 'loanTerm', ' months');
});
// Add listeners for numeric inputs to update sliders
document.getElementById('interestRateNumeric').addEventListener('input', function() {
updateNumericInput('interestRateNumeric', 'interestRate', '%');
});
document.getElementById('loanTermNumeric').addEventListener('input', function() {
updateNumericInput('loanTermNumeric', 'loanTerm', ' months');
});
// Trigger initial calculation on page load
calculateAutoLoan();
});