How Interest Rate Calculator

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Mortgage Payment Calculator

Estimate your monthly payments including taxes, insurance, and HOA fees.

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Yr
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Please enter valid numeric values greater than zero.
Total Monthly Payment
$0.00
Includes Principal, Interest, Taxes, Insurance & HOA
Principal & Interest $0.00
Property Tax (Mo.) $0.00
Home Insurance (Mo.) $0.00
HOA Fees $0.00
Total Loan Amount $0.00
Total Interest Cost $0.00

Understanding Your Mortgage Calculation

Purchasing a home is likely the largest financial commitment you will make in your lifetime. Understanding how your mortgage payment is calculated is crucial for budgeting and financial planning. This calculator breaks down the standard PITI components (Principal, Interest, Taxes, and Insurance) to give you a realistic view of your monthly housing costs.

What goes into a Monthly Mortgage Payment?

While the "sticker price" of a monthly mortgage payment often just refers to the loan repayment, the actual amount withdrawn from your bank account usually includes four key components:

  • Principal: The portion of your payment that pays down the actual balance of the loan. In the early years of a mortgage, this amount is small but grows over time.
  • Interest: The fee charged by the lender for borrowing the money. In the beginning, the majority of your payment goes toward interest.
  • Taxes: Property taxes assessed by your local government. Lenders often collect this monthly and place it in an escrow account to pay the bill when it's due.
  • Insurance: Homeowners insurance protects the property against damage. Like taxes, this is usually collected monthly into an escrow account.

How Interest Rates Affect Your Payment

Even a small fluctuation in interest rates can dramatically change your monthly payment and the total cost of the loan. For example, on a $300,000 loan, a 1% difference in interest rate can change your monthly payment by hundreds of dollars and your total interest paid by tens of thousands over the life of the loan.

The Impact of Down Payments

Putting more money down upfront reduces the principal loan amount. A standard down payment is often cited as 20%. If you put down less than 20%, you may be required to pay Private Mortgage Insurance (PMI), which protects the lender in case of default. Note that this calculator includes HOA fees but does not automatically calculate PMI, so be sure to factor that in if you have a low down payment.

Common Mortgage Questions

What is an Escrow Account?

An escrow account is a holding account managed by your lender. Instead of saving for big annual tax and insurance bills yourself, you pay one-twelfth of the estimated annual cost each month. The lender holds this money and pays the bills on your behalf when they are due.

Should I choose a 15-year or 30-year term?

A 30-year term offers lower monthly payments, making the home more affordable on a monthly basis. However, a 15-year term usually comes with a lower interest rate and results in significantly less total interest paid over the life of the loan, though the monthly payments are higher.

function calculateMortgage() { // 1. Get Input Values var homePrice = parseFloat(document.getElementById('homePrice').value); var downPayment = parseFloat(document.getElementById('downPayment').value); var interestRate = parseFloat(document.getElementById('interestRate').value); var loanTerm = parseFloat(document.getElementById('loanTerm').value); var propertyTaxYearly = parseFloat(document.getElementById('propertyTax').value); var homeInsuranceYearly = parseFloat(document.getElementById('homeInsurance').value); var hoaFees = parseFloat(document.getElementById('hoaFees').value); // 2. Element references var errorMsg = document.getElementById('errorMsg'); var resultsSection = document.getElementById('resultsSection'); // 3. Validation if (isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) || isNaN(loanTerm) || homePrice <= 0 || loanTerm home price if (principal < 0) principal = 0; // Monthly Interest Rate var monthlyRate = (interestRate / 100) / 12; // Total Number of Payments (Months) var numberOfPayments = loanTerm * 12; // Calculate Monthly Principal & Interest (Amortization Formula) // M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ] var monthlyPI = 0; if (interestRate === 0) { monthlyPI = principal / numberOfPayments; } else { var x = Math.pow(1 + monthlyRate, numberOfPayments); monthlyPI = (principal * monthlyRate * x) / (x – 1); } // Monthly Taxes and Insurance var monthlyTax = propertyTaxYearly / 12; var monthlyInsurance = homeInsuranceYearly / 12; // Total Monthly Payment var totalMonthlyPayment = monthlyPI + monthlyTax + monthlyInsurance + hoaFees; // Total Cost Calculations var totalCostOfLoan = (monthlyPI * numberOfPayments); var totalInterestPaid = totalCostOfLoan – principal; // 5. Update UI with formatted numbers var formatter = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD', minimumFractionDigits: 2 }); document.getElementById('totalMonthly').innerHTML = formatter.format(totalMonthlyPayment); document.getElementById('piAmount').innerHTML = formatter.format(monthlyPI); document.getElementById('taxAmount').innerHTML = formatter.format(monthlyTax); document.getElementById('insAmount').innerHTML = formatter.format(monthlyInsurance); document.getElementById('hoaAmount').innerHTML = formatter.format(hoaFees); document.getElementById('totalLoan').innerHTML = formatter.format(principal); document.getElementById('totalInterest').innerHTML = formatter.format(totalInterestPaid); // Show results resultsSection.style.display = 'block'; }

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