Mortgage Payment Calculator
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align-items: flex-start;
min-height: 100vh;
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Monthly Mortgage Payment Calculator
Calculate your estimated monthly mortgage payment.
Calculate Payment
$0.00
Your estimated monthly payment
Understanding Your Monthly Mortgage Payment
The monthly mortgage payment is the recurring amount you pay to your lender each month for your home loan. It typically includes several components, but the primary calculation is for the principal and interest (P&I). This calculator focuses on estimating that core P&I payment.
While this calculator provides an estimate for the Principal and Interest (P&I) portion of your mortgage, remember that your total monthly housing expense will likely be higher. Many mortgage payments also include:
Property Taxes: Funds set aside to pay your local property taxes.Homeowner's Insurance: Premiums for your homeowner's insurance policy.Private Mortgage Insurance (PMI): If your down payment is less than 20% of the home's price, PMI protects the lender.Homeowner Association (HOA) Fees: If applicable, for maintaining common areas in certain communities.
These additional costs are often collected by your lender and paid on your behalf, known as impounding. Your lender usually provides an "escrow account" for these payments.
The Math Behind the Mortgage Payment
Example Calculation
Let's break down an example:
Suppose you are taking out a mortgage with the following details:
Loan Amount (P)
$300,000
Annual Interest Rate
4.5%
Loan Term
30 Years
Here's how we'd calculate it:
Principal Loan Amount (P): $300,000Monthly Interest Rate (i): 4.5% annual / 12 months = 0.045 / 12 = 0.00375Total Number of Payments (n): 30 years * 12 months/year = 360
Using the formula:
M = 300000 [ 0.00375(1 + 0.00375)^360 ] / [ (1 + 0.00375)^360 – 1]
M = 300000 [ 0.00375(1.00375)^360 ] / [ (1.00375)^360 – 1]
M = 300000 [ 0.00375 * 3.74532 ) ] / [ 3.74532 – 1 ]
M = 300000 [ 0.0140449 ] / [ 2.74532 ]
M = 300000 * 0.0051156
M ≈ $1,534.70
So, the estimated monthly principal and interest payment for this loan would be approximately $1,534.70 .
Who Should Use This Calculator?
This calculator is ideal for:
Prospective homebuyers trying to understand the affordability of a property.
Current homeowners considering refinancing their mortgage.
Real estate agents and mortgage brokers assisting clients.
Anyone curious about how loan amount, interest rate, and loan term affect monthly payments.
By inputting different scenarios, you can get a clearer picture of your potential mortgage obligations and better plan your finances.
function calculateMortgagePayment() {
var principal = parseFloat(document.getElementById("principal").value);
var annualInterestRate = parseFloat(document.getElementById("annualInterestRate").value);
var loanTermYears = parseInt(document.getElementById("loanTermYears").value);
var resultElement = document.getElementById("result");
if (isNaN(principal) || principal <= 0) {
resultElement.innerHTML = "$0.00
Please enter a valid loan amount. ";
resultElement.style.backgroundColor = "#dc3545"; /* Error red */
return;
}
if (isNaN(annualInterestRate) || annualInterestRate < 0) {
resultElement.innerHTML = "$0.00
Please enter a valid annual interest rate. ";
resultElement.style.backgroundColor = "#dc3545"; /* Error red */
return;
}
if (isNaN(loanTermYears) || loanTermYears <= 0) {
resultElement.innerHTML = "$0.00
Please enter a valid loan term in years. ";
resultElement.style.backgroundColor = "#dc3545"; /* Error red */
return;
}
var monthlyInterestRate = annualInterestRate / 100 / 12;
var numberOfPayments = loanTermYears * 12;
var monthlyPayment;
if (monthlyInterestRate === 0) {
// Handle 0% interest rate case
monthlyPayment = principal / numberOfPayments;
} else {
// Standard mortgage payment formula
var factor = Math.pow(1 + monthlyInterestRate, numberOfPayments);
monthlyPayment = principal * (monthlyInterestRate * factor) / (factor – 1);
}
if (isNaN(monthlyPayment) || !isFinite(monthlyPayment)) {
resultElement.innerHTML = "$0.00
Calculation error. Check inputs. ";
resultElement.style.backgroundColor = "#dc3545"; /* Error red */
} else {
resultElement.innerHTML = "$" + monthlyPayment.toFixed(2) + "
Your estimated monthly payment ";
resultElement.style.backgroundColor = "var(–success-green)"; /* Success green */
}
}