Understanding how much house you can afford is a crucial first step in the home-buying process.
The Mortgage Affordability Calculator helps you estimate the maximum mortgage loan you can qualify for,
based on your income, existing debts, and estimated interest rates. This calculator considers key factors
that lenders use to determine your borrowing capacity, giving you a realistic financial picture.
Key Factors Explained:
Gross Monthly Income: This is your total income before taxes and deductions. Lenders typically look at this figure to assess your ability to handle a mortgage payment.
Estimated Monthly Debt Payments: This includes all your recurring monthly debt obligations, such as car loans, student loans, credit card minimum payments, and any other loans you have.
Estimated Interest Rate: The annual interest rate on the mortgage loan. This significantly impacts your monthly payment and the total interest paid over the life of the loan.
Loan Term (Years): The duration of the mortgage, usually 15 or 30 years. A longer term means lower monthly payments but more interest paid overall.
Down Payment: The upfront amount you pay towards the purchase price of the home. A larger down payment reduces the loan amount needed.
Lenders often use a debt-to-income ratio (DTI) to qualify borrowers. A common guideline is that your total monthly debt payments (including the potential mortgage payment) should not exceed 43% of your gross monthly income. This calculator provides an estimate, but your actual borrowing capacity will depend on the specific lender's underwriting criteria and your overall financial profile.
Calculate Your Mortgage Affordability
30 Years
15 Years
function calculateMortgageAffordability() {
var grossMonthlyIncome = parseFloat(document.getElementById("grossMonthlyIncome").value);
var monthlyDebtPayments = parseFloat(document.getElementById("monthlyDebtPayments").value);
var interestRate = parseFloat(document.getElementById("interestRate").value);
var loanTerm = parseInt(document.getElementById("loanTerm").value);
var downPayment = parseFloat(document.getElementById("downPayment").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (isNaN(grossMonthlyIncome) || isNaN(monthlyDebtPayments) || isNaN(interestRate) || isNaN(loanTerm) || isNaN(downPayment) ||
grossMonthlyIncome <= 0 || monthlyDebtPayments < 0 || interestRate < 0 || loanTerm <= 0 || downPayment < 0) {
resultDiv.innerHTML = "Please enter valid positive numbers for all fields.";
return;
}
// Lenders often use a maximum DTI of around 43%
var maxTotalMonthlyDebt = grossMonthlyIncome * 0.43;
var maxMortgagePayment = maxTotalMonthlyDebt – monthlyDebtPayments;
if (maxMortgagePayment 0) {
maxLoanAmount = maxMortgagePayment * (Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1) / (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments));
} else {
// Handle case of 0% interest rate (unlikely but for completeness)
maxLoanAmount = maxMortgagePayment * numberOfPayments;
}
// The maximum affordable home price is the loan amount plus the down payment
var maxHomePrice = maxLoanAmount + downPayment;
// Display results
resultDiv.innerHTML =
"
Estimated Affordability:
" +
"Maximum Affordable Monthly Mortgage Payment: $" + maxMortgagePayment.toFixed(2) + "" +
"Estimated Maximum Loan Amount: $" + maxLoanAmount.toFixed(2) + "" +
"Estimated Maximum Home Purchase Price: $" + maxHomePrice.toFixed(2) + "" +
"Note: This is an estimate. Actual loan approval depends on lender's criteria, credit score, and other factors.";
}