15 Years
30 Years
Excellent (760+)
Good (700-759)
Fair (620-699)
Poor (<620)
Your Affordability Estimate:
Enter your details and click "Calculate Affordability" to see your results.
Understanding Your Home Affordability with Zillow's Approach
Buying a home is one of the biggest financial decisions you'll make, and understanding what you can truly afford is crucial. The Zillow Affordability Calculator helps you estimate your maximum affordable home price and the associated monthly payments by considering key financial factors, much like lenders and real estate platforms do.
How Affordability is Determined
Lenders typically use debt-to-income (DTI) ratios to assess how much you can borrow. The two main ratios are:
Front-End Ratio (Housing Expense Ratio): This looks at your total monthly housing costs (principal, interest, property taxes, and home insurance, often called PITI, plus HOA fees) compared to your gross monthly income. A common guideline is that housing costs should not exceed 28% of your gross monthly income.
Back-End Ratio (Total Debt Ratio): This considers all your monthly debt payments (housing costs plus other debts like car loans, student loans, and credit card minimums) relative to your gross monthly income. A common guideline is that total debts should not exceed 36% of your gross monthly income.
Our calculator uses these principles to determine the maximum loan amount you might qualify for, and subsequently, your maximum affordable home price.
Key Factors in the Calculator:
Gross Monthly Income: Your total income before taxes and deductions. This is the foundation for DTI calculations.
Total Other Monthly Debts: Regular monthly payments for non-housing debts. Higher debts reduce your borrowing capacity.
Available Cash for Home Purchase: This is the upfront money you have for a down payment. A larger cash contribution reduces the loan amount needed and can increase your overall affordability.
Desired Loan Term (Years): The length of your mortgage. A longer term (e.g., 30 years) typically results in lower monthly payments but more interest paid over time.
Estimated Credit Score Range: Your credit score significantly impacts the mortgage rate you'll receive. A higher score generally leads to a lower rate, making a home more affordable. Our calculator uses typical rates associated with different credit score ranges.
Estimated Annual Property Tax Rate: Property taxes are a significant ongoing cost and vary widely by location. They are calculated as a percentage of the home's value.
Estimated Annual Home Insurance: Protects your home from damage and is usually required by lenders.
Estimated Monthly HOA Fees: If the property is part of a homeowners' association, these fees cover shared amenities and maintenance.
How to Use the Calculator:
Simply input your financial details into the respective fields. The calculator will then provide you with an estimate of the maximum home price you can afford and your estimated total monthly housing payment, helping you set realistic expectations for your home search.
Example Scenario:
Let's consider an example:
Gross Monthly Income: $7,000
Total Other Monthly Debts: $500
Available Cash for Home Purchase: $50,000
Desired Loan Term: 30 Years
Estimated Credit Score Range: Good (leading to an estimated 7.0% annual rate)
Estimated Annual Property Tax Rate: 1.2%
Estimated Annual Home Insurance: $1,200
Estimated Monthly HOA Fees: $50
Based on these inputs, the calculator would determine your maximum allowed monthly housing payment based on DTI rules. It would then work backward, factoring in property taxes (which depend on the home price), insurance, and HOA fees, to calculate the maximum loan amount you could qualify for. Adding your available cash to this loan amount gives you the maximum affordable home price. In this example, you might find an affordable home price around $280,000 with an estimated monthly payment of approximately $1,960.
Remember, this calculator provides an estimate. For precise figures, it's always best to consult with a financial advisor and a mortgage lender.
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function calculateAffordability() {
// Get input values
var grossMonthlyIncome = parseFloat(document.getElementById("grossMonthlyIncome").value);
var otherMonthlyDebts = parseFloat(document.getElementById("otherMonthlyDebts").value);
var availableCash = parseFloat(document.getElementById("availableCash").value);
var loanTermYears = parseInt(document.getElementById("loanTermYears").value);
var creditScoreRange = document.getElementById("creditScoreRange").value;
var annualPropertyTaxRate = parseFloat(document.getElementById("annualPropertyTaxRate").value);
var annualHomeInsurance = parseFloat(document.getElementById("annualHomeInsurance").value);
var monthlyHOAFees = parseFloat(document.getElementById("monthlyHOAFees").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
// Input validation
if (isNaN(grossMonthlyIncome) || grossMonthlyIncome < 0 ||
isNaN(otherMonthlyDebts) || otherMonthlyDebts < 0 ||
isNaN(availableCash) || availableCash < 0 ||
isNaN(loanTermYears) || loanTermYears <= 0 ||
isNaN(annualPropertyTaxRate) || annualPropertyTaxRate < 0 ||
isNaN(annualHomeInsurance) || annualHomeInsurance < 0 ||
isNaN(monthlyHOAFees) || monthlyHOAFees < 0) {
resultDiv.innerHTML = "Please enter valid positive numbers for all fields.";
return;
}
// Map credit score range to an estimated annual interest rate
var annualInterestRate;
switch (creditScoreRange) {
case "excellent": annualInterestRate = 0.065; break; // 6.5%
case "good": annualInterestRate = 0.070; break; // 7.0%
case "fair": annualInterestRate = 0.075; break; // 7.5%
case "poor": annualInterestRate = 0.080; break; // 8.0%
default: annualInterestRate = 0.070; // Default to good
}
var monthlyInterestRate = annualInterestRate / 12;
var numberOfPayments = loanTermYears * 12;
// Calculate maximum allowed total monthly housing payment based on DTI rules
var maxHousingPayment28 = grossMonthlyIncome * 0.28; // 28% front-end DTI
var maxHousingPayment36 = (grossMonthlyIncome * 0.36) – otherMonthlyDebts; // 36% back-end DTI
var maxAllowedTotalMonthlyHousingPayment = Math.min(maxHousingPayment28, maxHousingPayment36);
// Handle cases where DTI rules make borrowing impossible or very limited
if (maxAllowedTotalMonthlyHousingPayment 0) {
resultDiv.innerHTML = "Based on your income and debts, you may not qualify for a mortgage loan. However, with your available cash, you could potentially afford a home up to $" + cashOnlyAffordablePrice.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 }) + " if you pay cash. Your estimated monthly costs (taxes, insurance, HOA) would be $" + cashOnlyMonthlyPayment.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 }) + ".";
} else {
resultDiv.innerHTML = "Based on your inputs, you may not be able to afford a home at this time.";
}
return;
}
// Calculate fixed monthly housing costs (insurance and HOA)
var monthlyInsurance = annualHomeInsurance / 12;
var monthlyHOA = monthlyHOAFees;
// Calculate the maximum amount available for Principal, Interest, and Property Taxes (PI+T)
var maxPIPlusTaxPayment = maxAllowedTotalMonthlyHousingPayment – monthlyInsurance – monthlyHOA;
if (maxPIPlusTaxPayment 0) {
resultDiv.innerHTML = "Your fixed monthly housing costs (insurance and HOA) are too high relative to your income to allow for a mortgage. With your available cash, you could potentially afford a home up to $" + cashOnlyAffordablePrice.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 }) + " if you pay cash. Your estimated monthly costs (taxes, insurance, HOA) would be $" + cashOnlyMonthlyPayment.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 }) + ".";
} else {
resultDiv.innerHTML = "Based on your inputs, you may not be able to afford a home at this time.";
}
return;
}
// Calculate mortgage factor (monthly payment per dollar of loan)
var mortgageFactor;
if (monthlyInterestRate === 0) { // Cash purchase or 0% interest (unlikely for mortgage)
mortgageFactor = 1 / numberOfPayments; // Simple division for principal
} else {
mortgageFactor = (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments)) / (Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1);
}
// Calculate monthly property tax factor (per dollar of home price)
var taxFactor = (annualPropertyTaxRate / 100) / 12;
// Solve for Maximum Loan Amount (L) using the derived formula:
// L = (maxPIPlusTaxPayment – availableCash * taxFactor) / (mortgageFactor + taxFactor)
var denominator = mortgageFactor + taxFactor;
var numerator = maxPIPlusTaxPayment – (availableCash * taxFactor);
var maxLoanAmount = 0;
if (denominator > 0 && numerator > 0) {
maxLoanAmount = numerator / denominator;
}
// Ensure loan amount is not negative
if (maxLoanAmount 0) ? (maxLoanAmount * mortgageFactor) : 0;
var monthlyTaxes = (maxAffordablePrice * taxFactor);
var estimatedMonthlyPayment = monthlyPI + monthlyTaxes + monthlyInsurance + monthlyHOA;
// Format results
var formattedMaxAffordablePrice = maxAffordablePrice.toLocaleString('en-US', { style: 'currency', currency: 'USD', minimumFractionDigits: 2, maximumFractionDigits: 2 });
var formattedEstimatedMonthlyPayment = estimatedMonthlyPayment.toLocaleString('en-US', { style: 'currency', currency: 'USD', minimumFractionDigits: 2, maximumFractionDigits: 2 });
var formattedMaxLoanAmount = maxLoanAmount.toLocaleString('en-US', { style: 'currency', currency: 'USD', minimumFractionDigits: 2, maximumFractionDigits: 2 });
// Display results
resultDiv.innerHTML =
"Your Maximum Affordable Home Price is: " + formattedMaxAffordablePrice + "" +
"Your Estimated Total Monthly Payment (PITI + HOA) would be: " + formattedEstimatedMonthlyPayment + "" +
"This includes a maximum loan amount of: " + formattedMaxLoanAmount + "";
}