Calculate your estimated monthly mortgage payment.
Estimated Monthly Payment
$0.00
(Principal + Interest + Taxes + Insurance + PMI)
Understanding Your Mortgage Payment
When you take out a mortgage, your monthly payment (often referred to as PITI) typically consists of several components. This calculator helps you estimate the total monthly cost by considering:
Principal & Interest (P&I): This is the core of your mortgage payment, covering the repayment of the loan amount and the interest charged by the lender. The calculation uses the standard amortization formula.
Property Taxes: These are local government taxes based on the value of your property. We've included an estimate for your annual property taxes, divided by 12 to get a monthly figure.
Homeowner's Insurance: This protects you and the lender against damage to your property. An annual premium is included and divided by 12 for the monthly cost.
Private Mortgage Insurance (PMI): If your down payment is less than 20% of the home's purchase price, lenders often require PMI to protect themselves. This cost is also annualized and divided by 12.
How the Calculation Works
The monthly Principal & Interest (P&I) payment is calculated using the following formula, which is standard for amortizing loans:
$M = P \left[ \frac{i(1+i)^n}{(1+i)^n – 1} \right]$
Where:
$M$ = Your total monthly mortgage payment (P&I component)
$P$ = The principal loan amount
$i$ = Your monthly interest rate (annual rate divided by 12)
$n$ = The total number of payments over the loan's lifetime (loan term in years multiplied by 12)
To get the total estimated monthly payment, we add the monthly P&I component to the monthly property taxes, homeowner's insurance, and PMI.
Example Scenario
Let's say you are taking out a mortgage for $300,000 with an annual interest rate of 4.5% over a 30-year term. Your estimated annual property taxes are $3,600 ($300/month), annual homeowner's insurance is $1,200 ($100/month), and you don't need PMI ($0).
This calculator provides an estimate and does not include potential closing costs, HOA fees, or other charges. It's always recommended to consult with a mortgage professional for precise figures.
function calculateMortgage() {
var loanAmount = parseFloat(document.getElementById("loanAmount").value);
var annualInterestRate = parseFloat(document.getElementById("interestRate").value);
var loanTermYears = parseFloat(document.getElementById("loanTerm").value);
var annualPropertyTax = parseFloat(document.getElementById("propertyTax").value);
var annualHomeInsurance = parseFloat(document.getElementById("homeInsurance").value);
var annualPmi = parseFloat(document.getElementById("pmi").value);
var resultDiv = document.getElementById("result-value");
var resultHtml = "";
// Input validation
if (isNaN(loanAmount) || loanAmount <= 0) {
resultHtml = "Invalid Loan Amount";
} else if (isNaN(annualInterestRate) || annualInterestRate < 0) {
resultHtml = "Invalid Interest Rate";
} else if (isNaN(loanTermYears) || loanTermYears <= 0) {
resultHtml = "Invalid Loan Term";
} else if (isNaN(annualPropertyTax) || annualPropertyTax < 0) {
resultHtml = "Invalid Property Tax";
} else if (isNaN(annualHomeInsurance) || annualHomeInsurance < 0) {
resultHtml = "Invalid Homeowner's Insurance";
} else if (isNaN(annualPmi) || annualPmi 0 && numberOfPayments > 0) {
principalAndInterest = loanAmount * (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments)) / (Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1);
} else if (numberOfPayments > 0) { // Handle 0% interest rate case
principalAndInterest = loanAmount / numberOfPayments;
} else {
principalAndInterest = loanAmount; // If term is 0, pay immediately
}
var totalMonthlyPayment = principalAndInterest + monthlyPropertyTax + monthlyHomeInsurance + monthlyPmi;
resultHtml = "$" + totalMonthlyPayment.toFixed(2);
}
resultDiv.innerHTML = resultHtml;
}