Buying a home is a significant financial decision, and understanding how much mortgage you can realistically afford is crucial.
Our Mortgage Affordability Calculator helps you estimate your potential borrowing power based on your income, debts, and desired monthly payment.
This tool takes into account various factors to give you a clearer picture of your home-buying budget.
How to Use the Calculator
To use the calculator, simply enter the following information:
Gross Monthly Income: Your total income before taxes and deductions.
Existing Monthly Debt Payments: This includes credit card minimum payments, student loan payments, car loans, and any other recurring debt obligations (excluding your potential mortgage payment).
Estimated Monthly Property Taxes: Your best estimate of the annual property taxes divided by 12.
Estimated Monthly Homeowners Insurance: Your best estimate of the annual homeowners insurance premium divided by 12.
Estimated Monthly Private Mortgage Insurance (PMI): If you're putting down less than 20%, you'll likely need PMI. Estimate this monthly cost.
Desired Maximum Monthly Mortgage Payment (Principal & Interest): How much you are comfortable paying each month for just the principal and interest of your mortgage.
Current Mortgage Interest Rate: The estimated annual interest rate you expect for your mortgage.
Loan Term (Years): The length of the mortgage loan, typically 15 or 30 years.
Once you've entered these details, the calculator will estimate the maximum loan amount you can afford. Remember, this is an estimate, and a lender will perform a more thorough analysis.
Your Estimated Maximum Loan Amount
function calculateMortgageAffordability() {
var grossMonthlyIncome = parseFloat(document.getElementById("grossMonthlyIncome").value);
var existingMonthlyDebt = parseFloat(document.getElementById("existingMonthlyDebt").value);
var monthlyPropertyTaxes = parseFloat(document.getElementById("monthlyPropertyTaxes").value);
var monthlyHomeownersInsurance = parseFloat(document.getElementById("monthlyHomeownersInsurance").value);
var monthlyPMI = parseFloat(document.getElementById("monthlyPMI").value);
var desiredMaxMortgagePAndI = parseFloat(document.getElementById("desiredMaxMortgagePAndI").value);
var interestRate = parseFloat(document.getElementById("interestRate").value);
var loanTermYears = parseFloat(document.getElementById("loanTermYears").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (isNaN(grossMonthlyIncome) || grossMonthlyIncome <= 0 ||
isNaN(existingMonthlyDebt) || existingMonthlyDebt < 0 ||
isNaN(monthlyPropertyTaxes) || monthlyPropertyTaxes < 0 ||
isNaN(monthlyHomeownersInsurance) || monthlyHomeownersInsurance < 0 ||
isNaN(monthlyPMI) || monthlyPMI < 0 ||
isNaN(desiredMaxMortgagePAndI) || desiredMaxMortgagePAndI <= 0 ||
isNaN(interestRate) || interestRate <= 0 ||
isNaN(loanTermYears) || loanTermYears maxTotalHousingPayment) {
resultDiv.innerHTML = "Your desired total housing payment (including P&I, taxes, insurance, and PMI) exceeds the typical 28% of your gross monthly income. Please adjust your desired maximum P&I payment or other costs.";
return;
}
var currentTotalDebtPayment = existingMonthlyDebt + desiredMaxMortgagePAndI + monthlyPropertyTaxes + monthlyHomeownersInsurance + monthlyPMI;
if (currentTotalDebtPayment > maxTotalDebtPayment) {
resultDiv.innerHTML = "Your total monthly debt payments (including existing debts and estimated housing costs) exceed the typical 36% of your gross monthly income. Please adjust your desired maximum P&I payment or reduce existing debts.";
return;
}
// Calculate the maximum loan amount based on the desired monthly P&I payment
var monthlyInterestRate = interestRate / 100 / 12;
var numberOfPayments = loanTermYears * 12;
var maxLoanAmount = 0;
if (monthlyInterestRate > 0) {
maxLoanAmount = desiredMaxMortgagePAndI * (1 – Math.pow(1 + monthlyInterestRate, -numberOfPayments)) / monthlyInterestRate;
} else { // Handle case for 0% interest rate, though unrealistic for mortgages
maxLoanAmount = desiredMaxMortgagePAndI * numberOfPayments;
}
if (maxLoanAmount > 0) {
resultDiv.innerHTML = "Based on your inputs, the estimated maximum loan amount you could afford is: $" + maxLoanAmount.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,') + "";
} else {
resultDiv.innerHTML = "Could not calculate a valid loan amount with the provided inputs.";
}
}
.calculator-container {
display: flex;
flex-wrap: wrap;
gap: 20px;
font-family: sans-serif;
}
.input-section, .result-section {
flex: 1;
min-width: 300px;
padding: 15px;
border: 1px solid #ccc;
border-radius: 5px;
background-color: #f9f9f9;
}
.input-section label {
display: block;
margin-bottom: 5px;
font-weight: bold;
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.input-section input[type="number"] {
width: calc(100% – 12px);
padding: 8px;
margin-bottom: 10px;
border: 1px solid #ddd;
border-radius: 4px;
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.input-section button {
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font-weight: bold;
color: #28a745;
}