Estimate your monthly house payments and total interest costs.
30 Years Fixed
20 Years Fixed
15 Years Fixed
10 Years Fixed
Principal & Interest:$0.00
Tax & Insurance (Monthly):$0.00
Total Monthly Payment:$0.00
Total Interest Paid:$0.00
How to Use the Mortgage Payment Calculator
Planning for a new home involves more than just the sticker price. Our Mortgage Payment Calculator helps you break down the financial commitment of homeownership by factoring in interest rates, down payments, taxes, and insurance. To get started, enter the home price and the amount you intend to pay upfront (the down payment).
Understanding the Formula
The core of the calculation relies on the standard amortization formula:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
M: Total monthly principal and interest payment.
P: Principal loan amount (Home Price – Down Payment).
i: Monthly interest rate (Annual Rate divided by 12 months).
n: Number of months in the loan term (Years multiplied by 12).
Factors That Influence Your Monthly Payment
Several variables can significantly change what you pay each month:
Interest Rates: Even a 1% difference in your interest rate can result in tens of thousands of dollars saved or spent over the life of the loan.
Loan Term: A 15-year mortgage usually has a lower interest rate but higher monthly payments compared to a 30-year mortgage, though it saves you massive amounts in interest.
Down Payment: Putting down 20% or more often helps you avoid Private Mortgage Insurance (PMI), further reducing your monthly costs.
Escrow Costs: Property taxes and homeowners insurance are often rolled into your monthly mortgage payment. These costs vary significantly by state and county.
Example Calculation
Suppose you purchase a home for $400,000 with a 20% down payment ($80,000). You secure a 30-year fixed rate at 6.5%. Your annual property taxes are $3,000 and insurance is $1,200.
Loan Amount: $320,000
Monthly Principal & Interest: $2,022.62
Monthly Tax & Insurance: $350.00
Total Monthly Payment: $2,372.62
Over the course of 30 years, you would pay approximately $408,144 in interest alone.
function calculateMortgage() {
var homePrice = parseFloat(document.getElementById("homePrice").value);
var downPayment = parseFloat(document.getElementById("downPayment").value);
var annualRate = parseFloat(document.getElementById("interestRate").value);
var loanTermYears = parseInt(document.getElementById("loanTerm").value);
var annualTax = parseFloat(document.getElementById("propertyTax").value) || 0;
var annualInsurance = parseFloat(document.getElementById("insurance").value) || 0;
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(annualRate) || homePrice <= 0) {
alert("Please enter valid numbers for price, down payment, and interest rate.");
return;
}
var principal = homePrice – downPayment;
if (principal <= 0) {
alert("Down payment cannot be greater than or equal to the home price.");
return;
}
var monthlyRate = (annualRate / 100) / 12;
var totalMonths = loanTermYears * 12;
var monthlyPI = 0;
if (monthlyRate === 0) {
monthlyPI = principal / totalMonths;
} else {
monthlyPI = principal * (monthlyRate * Math.pow(1 + monthlyRate, totalMonths)) / (Math.pow(1 + monthlyRate, totalMonths) – 1);
}
var monthlyTaxIns = (annualTax + annualInsurance) / 12;
var totalMonthly = monthlyPI + monthlyTaxIns;
var totalInterest = (monthlyPI * totalMonths) – principal;
document.getElementById("principalInterestDisplay").innerText = "$" + monthlyPI.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("taxInsuranceDisplay").innerText = "$" + monthlyTaxIns.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("totalMonthlyDisplay").innerText = "$" + totalMonthly.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("totalInterestDisplay").innerText = "$" + totalInterest.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("mortgageResult").style.display = "block";
}