Calculate your estimated monthly mortgage payment, including Principal, Interest, Property Taxes, and Private Mortgage Insurance (PMI).
15 Years
20 Years
25 Years
30 Years
35 Years
40 Years
(Usually required if down payment is less than 20%)
Estimated Monthly Payment:
$0.00
Understanding Your Mortgage Payment Components
Your monthly mortgage payment is more than just paying back the loan amount. It typically consists of several key components that ensure your lender is protected and the property is maintained. This calculator helps you estimate your total monthly housing cost, including:
Principal & Interest (P&I): This is the core of your mortgage payment. Principal is the amount you borrow, and Interest is the cost of borrowing that money. The P&I portion is calculated using an amortization formula, where payments are higher in the beginning and gradually shift more towards principal over time.
Property Taxes: Paid annually to your local government, these taxes are usually collected by your lender in monthly installments and held in an escrow account. They are based on the assessed value of your property and local tax rates.
Homeowners Insurance: This covers your property against damages like fire, theft, or natural disasters. Lenders require you to have this coverage and often collect it monthly in escrow.
Private Mortgage Insurance (PMI): If your down payment is less than 20% of the home's purchase price, lenders typically require PMI. This protects the lender in case you default on the loan. PMI is usually a percentage of the loan amount and is paid monthly until your loan-to-value ratio reaches a certain threshold (typically 78-80%).
How the Calculation Works
The calculator uses the following steps:
Loan Amount: Calculated as Home Price - Down Payment.
Loan Term in Months: Calculated as Loan Term (Years) * 12.
Principal & Interest (P&I) Payment: Calculated using the standard mortgage payment formula (annuity formula):
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
Where:
M = Monthly Payment (P&I)
P = Loan Amount
i = Monthly Interest Rate
n = Total Number of Payments (Loan Term in Months)
Monthly Property Taxes: Calculated as Annual Property Taxes / 12.
Monthly Homeowners Insurance: Calculated as Annual Homeowners Insurance / 12.
Monthly PMI: Calculated as (Loan Amount * (PMI Rate / 100)) / 12. This is only added if the down payment is less than 20% of the home price.
Total Monthly Payment: Sum of P&I, Monthly Taxes, Monthly Insurance, and Monthly PMI.
Important Considerations:
This calculator provides an estimate. Actual costs may vary based on lender fees, specific insurance policies, and changes in property tax assessments.
The PMI calculation assumes a constant rate. Some PMI policies may have different structures.
This calculation does not include potential costs like Homeowners Association (HOA) fees, flood insurance (if required), or other potential assessments.
var interestRateSlider = document.getElementById("interestRateSlider");
var interestRateInput = document.getElementById("interestRate");
var pmiRateSlider = document.getElementById("pmiRateSlider");
var pmiRateInput = document.getElementById("pmiRate");
// Sync sliders and input fields
interestRateSlider.oninput = function() {
interestRateInput.value = this.value;
calculateMortgage();
}
interestRateInput.oninput = function() {
if (parseFloat(this.value) >= parseFloat(interestRateSlider.min) && parseFloat(this.value) = parseFloat(pmiRateSlider.min) && parseFloat(this.value) <= parseFloat(pmiRateSlider.max)) {
pmiRateSlider.value = this.value;
calculateMortgage();
} else {
this.value = pmiRateSlider.value; // Reset if out of bounds
}
}
function calculateMortgage() {
var homePrice = parseFloat(document.getElementById("homePrice").value);
var downPayment = parseFloat(document.getElementById("downPayment").value);
var annualInterestRate = parseFloat(document.getElementById("interestRate").value);
var loanTermYears = parseInt(document.getElementById("loanTerm").value);
var annualTaxes = parseFloat(document.getElementById("annualTaxes").value);
var annualHomeownersInsurance = parseFloat(document.getElementById("annualHomeownersInsurance").value);
var pmiRate = parseFloat(document.getElementById("pmiRate").value);
var resultDiv = document.getElementById("result");
// Basic validation
if (isNaN(homePrice) || homePrice <= 0 ||
isNaN(downPayment) || downPayment < 0 ||
isNaN(annualInterestRate) || annualInterestRate <= 0 ||
isNaN(loanTermYears) || loanTermYears <= 0 ||
isNaN(annualTaxes) || annualTaxes < 0 ||
isNaN(annualHomeownersInsurance) || annualHomeownersInsurance < 0 ||
isNaN(pmiRate) || pmiRate < 0) {
resultDiv.innerHTML = 'Please enter valid numbers for all fields.$0.00′;
return;
}
if (downPayment >= homePrice) {
resultDiv.innerHTML = 'Down payment cannot be more than or equal to home price.$0.00′;
return;
}
var loanAmount = homePrice – downPayment;
var monthlyInterestRate = (annualInterestRate / 100) / 12;
var loanTermMonths = loanTermYears * 12;
var pmiApplicable = (downPayment / homePrice) 0) {
pniPayment = loanAmount * (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, loanTermMonths)) / (Math.pow(1 + monthlyInterestRate, loanTermMonths) – 1);
} else { // Handle 0% interest rate case (unlikely for mortgages but good practice)
pniPayment = loanAmount / loanTermMonths;
}
var monthlyTaxes = annualTaxes / 12;
var monthlyInsurance = annualHomeownersInsurance / 12;
var totalMonthlyPayment = pniPayment + monthlyTaxes + monthlyInsurance + monthlyPmi;
resultDiv.innerHTML = 'Estimated Monthly Payment:$' + totalMonthlyPayment.toFixed(2);
}
// Initial calculation on page load
document.addEventListener('DOMContentLoaded', calculateMortgage);