<input type="number" id="pmi" value="0.5" min="0" step="0.1" title="Private Mortgage Insurance if down payment
Please enter valid positive numbers for all fields.
Total Monthly Payment$0.00
Principal & Interest$0.00
Property Tax$0.00
Home Insurance$0.00
PMI (Mortgage Insurance)$0.00
Total Payment$0.00
Loan Summary:
Loan Amount: $0
Total Interest Paid: $0
Payoff Date: –
Understanding Your Mortgage Calculation
Buying a home is one of the most significant financial decisions you will make. This Mortgage Payment Calculator helps you estimate your monthly financial commitment by breaking down the costs associated with homeownership. Unlike simple calculators that only show principal and interest, this tool accounts for property taxes, homeowners insurance, and PMI (Private Mortgage Insurance).
The Components of a Mortgage Payment (PITI)
Most mortgage payments are comprised of four main parts, often referred to by the acronym PITI:
Principal: The portion of your payment that goes towards paying down the original loan amount. In the early years of a mortgage, this amount is small but grows over time.
Interest: The cost of borrowing money. Initially, interest makes up the bulk of your monthly payment.
Taxes: Property taxes assessed by your local government. Lenders typically collect this monthly and hold it in an escrow account to pay the bill when it's due.
Insurance: Homeowners insurance protects your property against damage. Like taxes, this is often collected monthly into an escrow account.
What is PMI?
Private Mortgage Insurance (PMI) is usually required if your down payment is less than 20% of the home's purchase price. It protects the lender in case you default on the loan. The cost of PMI varies depending on your credit score and the size of your down payment, typically ranging from 0.3% to 1.5% of the original loan amount annually. Once you reach 20% equity in your home, you can usually request to have PMI removed.
How Interest Rates Affect Buying Power
Even a small change in interest rates can significantly impact your monthly payment and the total cost of the loan. For example, on a $300,000 loan, a 1% increase in interest rate can increase your monthly payment by hundreds of dollars and your total interest paid by over $60,000 over the life of a 30-year loan.
30-Year vs. 15-Year Mortgages
Choosing the term of your loan is a trade-off between monthly affordability and total cost:
30-Year Mortgage: Offers lower monthly payments, making the home more affordable on a month-to-month basis, but you will pay significantly more in interest over the life of the loan.
15-Year Mortgage: Requires higher monthly payments, but you build equity much faster and usually secure a lower interest rate, saving thousands in total interest costs.
Using This Calculator for Budgeting
Use the inputs above to scenario-plan your home purchase. Try adjusting the Down Payment to see how it affects PMI and your monthly obligation. Adjust the Home Price to determine what you can realistically afford based on your current monthly budget.
function calculateMortgage() {
// 1. Get DOM elements
var homePriceInput = document.getElementById("homePrice");
var downPaymentInput = document.getElementById("downPayment");
var interestRateInput = document.getElementById("interestRate");
var loanTermInput = document.getElementById("loanTerm");
var propertyTaxInput = document.getElementById("propertyTax");
var homeInsuranceInput = document.getElementById("homeInsurance");
var pmiInput = document.getElementById("pmi");
var errorMsg = document.getElementById("error-message");
var resultsArea = document.getElementById("results-area");
// 2. Parse values
var homePrice = parseFloat(homePriceInput.value);
var downPayment = parseFloat(downPaymentInput.value);
var interestRate = parseFloat(interestRateInput.value);
var loanTermYears = parseInt(loanTermInput.value);
var yearlyTax = parseFloat(propertyTaxInput.value);
var yearlyInsurance = parseFloat(homeInsuranceInput.value);
var yearlyPmiPercent = parseFloat(pmiInput.value);
// 3. Validation
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) ||
isNaN(loanTermYears) || isNaN(yearlyTax) || isNaN(yearlyInsurance) || isNaN(yearlyPmiPercent)) {
errorMsg.style.display = "block";
resultsArea.style.display = "none";
return;
}
if (homePrice <= 0 || loanTermYears = home price
if (loanAmount 0) {
if (interestRate === 0) {
monthlyPI = loanAmount / numberOfPayments;
} else {
// Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var mathPower = Math.pow(1 + monthlyRate, numberOfPayments);
monthlyPI = loanAmount * (monthlyRate * mathPower) / (mathPower – 1);
}
}
// Calculate Escrow Items
var monthlyTax = yearlyTax / 12;
var monthlyInsurance = yearlyInsurance / 12;
// Calculate PMI
// PMI generally applies if LTV > 80% (Down payment < 20%)
var ltv = (loanAmount / homePrice) * 100;
var monthlyPMI = 0;
// Simple PMI logic: if down payment is less than 20% of home price, apply PMI
if (downPayment 0) {
monthlyPMI = (loanAmount * (yearlyPmiPercent / 100)) / 12;
}
// Total Monthly
var totalMonthly = monthlyPI + monthlyTax + monthlyInsurance + monthlyPMI;
// Total Interest over life of loan
var totalPaymentOverLife = (monthlyPI * numberOfPayments);
var totalInterest = totalPaymentOverLife – loanAmount;
// Payoff Date (Current Date + Term)
var today = new Date();
var payoffYear = today.getFullYear() + loanTermYears;
var payoffMonth = today.toLocaleString('default', { month: 'long' });
var payoffDateString = payoffMonth + " " + payoffYear;
// 5. Display Results
resultsArea.style.display = "block";
document.getElementById("totalMonthlyDisplay").innerText = formatCurrency(totalMonthly);
document.getElementById("piDisplay").innerText = formatCurrency(monthlyPI);
document.getElementById("taxDisplay").innerText = formatCurrency(monthlyTax);
document.getElementById("insDisplay").innerText = formatCurrency(monthlyInsurance);
document.getElementById("pmiDisplay").innerText = formatCurrency(monthlyPMI);
document.getElementById("totalCheckDisplay").innerText = formatCurrency(totalMonthly);
document.getElementById("loanAmountDisplay").innerText = formatCurrency(loanAmount);
document.getElementById("totalInterestDisplay").innerText = formatCurrency(totalInterest);
document.getElementById("payoffDateDisplay").innerText = payoffDateString;
// Scroll to results on mobile
if(window.innerWidth < 600) {
resultsArea.scrollIntoView({behavior: "smooth"});
}
}
function formatCurrency(num) {
return "$" + num.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
}