Purchasing a home in New Jersey involves a significant financial commitment. The monthly mortgage payment is often the largest expense for homeowners. This New Jersey Mortgage Calculator helps you estimate your total monthly housing cost by breaking down the key components. It's designed to provide a clear picture of what you can expect to pay each month, including principal, interest, taxes, insurance, and potential private mortgage insurance (PMI) and Homeowners Association (HOA) fees.
Key Components of Your Monthly Payment:
Principal & Interest (P&I): This is the core of your mortgage payment. It covers the loan amount you borrowed and the interest charged by the lender. The calculation for P&I is standardized using an amortization formula.
Property Taxes: New Jersey is known for its high property taxes. Your estimated monthly property tax is calculated by taking the annual property tax rate (as a percentage of the home's value) and dividing it by 12.
Homeowners Insurance: This covers damage to your home. The calculator uses your estimated annual premium, divided by 12.
Private Mortgage Insurance (PMI): If your down payment is less than 20% of the home's purchase price, lenders typically require PMI to protect themselves. The calculator estimates this monthly cost based on the annual PMI rate and the loan amount.
Homeowners Association (HOA) Fees: If your property is part of an HOA, you'll have monthly or annual fees. This calculator includes monthly HOA fees.
How the New Jersey Mortgage Calculator Works:
The calculator uses standard formulas to estimate your monthly payment. The total estimated monthly payment is the sum of the monthly P&I, monthly property taxes, monthly homeowners insurance, monthly PMI (if applicable), and monthly HOA fees.
Principal & Interest (P&I) Calculation:
The formula used is the standard mortgage payment formula:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
Where:
M = Your total monthly mortgage payment (Principal & Interest)
P = The principal loan amount (Home Purchase Price – Down Payment)
i = Your monthly interest rate (Annual Interest Rate / 12 / 100)
n = The total number of payments over the loan's lifetime (Loan Term in Years * 12)
This calculator provides an estimate. Your actual mortgage payment may vary based on lender fees, specific tax assessments, insurance policy details, and changes in interest rates. It's always recommended to consult with a qualified mortgage professional for personalized advice and accurate figures.
function calculateMortgage() {
var homePrice = parseFloat(document.getElementById("homePrice").value);
var downPayment = parseFloat(document.getElementById("downPayment").value);
var loanTermYears = parseInt(document.getElementById("loanTerm").value);
var annualInterestRate = parseFloat(document.getElementById("annualInterestRate").value);
var propertyTaxRate = parseFloat(document.getElementById("propertyTaxRate").value);
var homeownersInsurance = parseFloat(document.getElementById("homeownersInsurance").value);
var pmiRate = parseFloat(document.getElementById("pmiRate").value);
var hoaFees = parseFloat(document.getElementById("hoaFees").value);
var resultElement = document.getElementById("result");
// Input validation
if (isNaN(homePrice) || homePrice <= 0 ||
isNaN(downPayment) || downPayment < 0 ||
isNaN(loanTermYears) || loanTermYears <= 0 ||
isNaN(annualInterestRate) || annualInterestRate < 0 ||
isNaN(propertyTaxRate) || propertyTaxRate < 0 ||
isNaN(homeownersInsurance) || homeownersInsurance < 0 ||
isNaN(pmiRate) || pmiRate < 0 ||
isNaN(hoaFees) || hoaFees < 0) {
resultElement.innerHTML = "$0.00Please enter valid numbers for all fields.";
return;
}
if (downPayment > homePrice) {
resultElement.innerHTML = "$0.00Down payment cannot exceed home price.";
return;
}
var loanAmount = homePrice – downPayment;
var monthlyInterestRate = (annualInterestRate / 100) / 12;
var numberOfPayments = loanTermYears * 12;
var principalAndInterest = 0;
if (monthlyInterestRate > 0 && numberOfPayments > 0) {
principalAndInterest = loanAmount * (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments)) / (Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1);
} else if (loanAmount > 0) {
principalAndInterest = loanAmount / numberOfPayments; // Simple division if interest is 0
}
var monthlyPropertyTax = (homePrice * propertyTaxRate / 100) / 12;
var monthlyHomeownersInsurance = homeownersInsurance / 12;
var monthlyPMI = 0;
if (downPayment < (homePrice * 0.20)) { // PMI is typically required if down payment is less than 20%
monthlyPMI = (loanAmount * pmiRate / 100) / 12;
}
var totalMonthlyPayment = principalAndInterest + monthlyPropertyTax + monthlyHomeownersInsurance + monthlyPMI + hoaFees;
if (isNaN(totalMonthlyPayment) || totalMonthlyPayment < 0) {
resultElement.innerHTML = "$0.00Calculation error. Check inputs.";
} else {
resultElement.innerHTML = "$" + totalMonthlyPayment.toFixed(2) +
"Estimated Monthly Payment (PITI + HOA)";
}
}