Calculating your potential monthly mortgage payment is a crucial step when considering a home purchase,
especially with a trusted institution like Navy Federal Credit Union. This calculator helps you estimate
your Principal and Interest (P&I) payment, which is the core component of your mortgage.
While this calculator focuses on P&I, remember that your total monthly housing expense (often called PITI)
will typically include Property Taxes, Homeowners Insurance, and potentially
Private Mortgage Insurance (PMI) or HOA fees. Navy Federal, like other lenders,
may escrow these amounts and collect them with your monthly payment.
The Math Behind the Calculation
The formula used to calculate the monthly mortgage payment (M) is a standard annuity formula:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
Where:
P = Principal Loan Amount (the total amount borrowed)
n = Total Number of Payments (Loan Term in Years * 12)
How to Use the Navy Federal Mortgage Payment Calculator
1. Loan Amount: Enter the total amount you plan to borrow for your home purchase. This is usually the home's price minus your down payment.
2. Annual Interest Rate: Input the yearly interest rate offered by Navy Federal for your mortgage. Use the percentage value (e.g., 4.5 for 4.5%).
3. Loan Term (Years): Specify the duration of the loan in years (e.g., 15, 20, or 30 years).
Click "Calculate Payment," and the calculator will provide an estimated monthly P&I payment.
Why Use This Calculator?
This tool is invaluable for:
Budgeting: Understand how much your potential mortgage payment will be and if it fits within your budget.
Comparing Offers: See how different interest rates or loan terms affect your monthly payment.
Financial Planning: Get a clearer picture of your long-term financial commitment.
Navy Federal Specifics: While the formula is standard, understanding potential rates and terms available through Navy Federal helps tailor the results to your specific membership benefits.
Disclaimer: This calculator provides an estimate for Principal and Interest payments only. It does not include taxes, insurance, or other potential fees. Actual loan terms and payments may vary. Consult directly with Navy Federal Credit Union for precise loan figures and pre-approval.
function calculateMortgagePayment() {
var principal = parseFloat(document.getElementById("loanAmount").value);
var annualRate = parseFloat(document.getElementById("interestRate").value);
var years = parseInt(document.getElementById("loanTermYears").value);
var resultElement = document.getElementById("result");
if (isNaN(principal) || isNaN(annualRate) || isNaN(years) || principal <= 0 || annualRate < 0 || years <= 0) {
resultElement.innerHTML = "Please enter valid positive numbers for all fields.";
return;
}
var monthlyRate = (annualRate / 100) / 12;
var numberOfPayments = years * 12;
var monthlyPayment;
if (monthlyRate === 0) {
monthlyPayment = principal / numberOfPayments;
} else {
monthlyPayment = principal * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) - 1);
}
if (isNaN(monthlyPayment) || monthlyPayment === Infinity) {
resultElement.innerHTML = "Calculation error. Please check inputs.";
return;
}
resultElement.innerHTML = "$" + monthlyPayment.toFixed(2) + "Estimated P&I Payment";
}