Estimate your monthly payments, including taxes and insurance.
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Estimated Monthly Payment
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Principal & Interest
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Property Tax
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Home Insurance
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HOA Fees
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Loan Amount:– •
Total Interest:–
How to Use This Mortgage Calculator
Buying a home is one of the most significant financial decisions you'll make in your lifetime. Understanding exactly how much house you can afford and what your monthly obligations will be is crucial. This specific Mortgage Calculator is designed to give you a comprehensive breakdown of your monthly housing costs, going beyond just the loan repayment.
Simply enter the home price, your planned down payment, the loan term (usually 15 or 30 years), and your expected interest rate. To get the most accurate "out-of-pocket" monthly figure, ensure you also estimate your annual property taxes, home insurance premiums, and any applicable Homeowners Association (HOA) fees.
Understanding Your Monthly Payment Components
Your monthly mortgage payment is typically comprised of four main parts, often referred to as PITI:
Principal: The portion of your payment that goes toward paying down the loan balance.
Interest: The cost of borrowing money from your lender. In the early years of a mortgage, a larger portion of your payment goes toward interest.
Taxes: Property taxes assessed by your local government, usually held in escrow by your lender and paid annually.
Insurance: Homeowners insurance protects your property against damage and liability. Lenders require this to protect their investment.
How Interest Rates Impact Affordability
Even a small fluctuation in interest rates can significantly affect your purchasing power. For example, on a $300,000 loan, a 1% increase in interest rate can increase your monthly principal and interest payment by nearly $200. Using this calculator allows you to test different rate scenarios to see how they impact your monthly budget.
The Role of the Down Payment
Your down payment reduces the total loan amount and affects your Loan-to-Value (LTV) ratio. A larger down payment (typically 20% or more) often secures a lower interest rate and eliminates the need for Private Mortgage Insurance (PMI), which protects the lender if you default.
Frequently Asked Questions
What is a good rule of thumb for mortgage affordability?
Many financial experts recommend the 28/36 rule: spend no more than 28% of your gross monthly income on housing expenses and no more than 36% on total debt.
Do I need 20% down?
While 20% is ideal to avoid PMI, many loan programs allow for much lower down payments, such as 3.5% for FHA loans or even 0% for VA loans.
function calculateMortgage() {
// 1. Get Input Values
var homePrice = parseFloat(document.getElementById("homePrice").value);
var downPayment = parseFloat(document.getElementById("downPayment").value);
var loanTermYears = parseFloat(document.getElementById("loanTerm").value);
var interestRateAnnual = parseFloat(document.getElementById("interestRate").value);
var propertyTaxAnnual = parseFloat(document.getElementById("propertyTax").value);
var homeInsuranceAnnual = parseFloat(document.getElementById("homeInsurance").value);
var hoaFeesMonthly = parseFloat(document.getElementById("hoaFees").value);
// 2. Validate Inputs
if (isNaN(homePrice) || homePrice < 0) homePrice = 0;
if (isNaN(downPayment) || downPayment < 0) downPayment = 0;
if (isNaN(loanTermYears) || loanTermYears <= 0) loanTermYears = 30; // default 30
if (isNaN(interestRateAnnual) || interestRateAnnual < 0) interestRateAnnual = 0;
if (isNaN(propertyTaxAnnual) || propertyTaxAnnual < 0) propertyTaxAnnual = 0;
if (isNaN(homeInsuranceAnnual) || homeInsuranceAnnual < 0) homeInsuranceAnnual = 0;
if (isNaN(hoaFeesMonthly) || hoaFeesMonthly < 0) hoaFeesMonthly = 0;
// 3. Core Calculation Logic
var loanAmount = homePrice – downPayment;
// Prevent negative loan amount
if (loanAmount 0) {
if (interestRateAnnual === 0) {
// Simple division if 0% interest
monthlyPrincipalInterest = loanAmount / numberOfPayments;
} else {
// Standard Amortization Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var mathPower = Math.pow(1 + monthlyInterestRate, numberOfPayments);
monthlyPrincipalInterest = loanAmount * (monthlyInterestRate * mathPower) / (mathPower – 1);
}
}
// Monthly Taxes and Insurance
var monthlyTax = propertyTaxAnnual / 12;
var monthlyInsurance = homeInsuranceAnnual / 12;
// Total Monthly Payment
var totalMonthlyPayment = monthlyPrincipalInterest + monthlyTax + monthlyInsurance + hoaFeesMonthly;
// Total Interest Paid over life of loan
var totalPayments = monthlyPrincipalInterest * numberOfPayments;
var totalInterest = totalPayments – loanAmount;
if (totalInterest < 0) totalInterest = 0;
// 4. Formatting Output Functions
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2,
maximumFractionDigits: 2
});
// 5. Update UI
document.getElementById("totalMonthlyDisplay").innerText = formatter.format(totalMonthlyPayment);
document.getElementById("piDisplay").innerText = formatter.format(monthlyPrincipalInterest);
document.getElementById("taxDisplay").innerText = formatter.format(monthlyTax);
document.getElementById("insuranceDisplay").innerText = formatter.format(monthlyInsurance);
document.getElementById("hoaDisplay").innerText = formatter.format(hoaFeesMonthly);
document.getElementById("loanAmountDisplay").innerText = formatter.format(loanAmount);
document.getElementById("totalInterestDisplay").innerText = formatter.format(totalInterest);
// Show result container
document.getElementById("resultContainer").style.display = "block";
}