.ma-calculator-container {
font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
background: #fff;
padding: 30px;
border-radius: 8px;
box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}
.ma-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
.ma-input-group {
margin-bottom: 15px;
}
.ma-input-group label {
display: block;
font-weight: 600;
margin-bottom: 5px;
color: #333;
}
.ma-input-group input, .ma-input-group select {
width: 100%;
padding: 10px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 16px;
}
.ma-input-group .helper-text {
font-size: 12px;
color: #666;
margin-top: 4px;
}
.ma-btn {
background-color: #2c3e50;
color: white;
border: none;
padding: 15px 30px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
width: 100%;
margin-top: 10px;
transition: background 0.3s;
}
.ma-btn:hover {
background-color: #34495e;
}
#ma-result {
margin-top: 30px;
padding: 20px;
background-color: #f8f9fa;
border-left: 5px solid #27ae60;
display: none;
}
.ma-result-header {
font-size: 18px;
color: #555;
margin-bottom: 10px;
}
.ma-result-value {
font-size: 36px;
font-weight: 800;
color: #27ae60;
margin-bottom: 20px;
}
.ma-breakdown {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 15px;
border-top: 1px solid #ddd;
padding-top: 15px;
}
.ma-breakdown-item span {
display: block;
font-size: 14px;
color: #666;
}
.ma-breakdown-item strong {
display: block;
font-size: 18px;
color: #333;
}
.ma-content {
margin-top: 50px;
line-height: 1.6;
color: #333;
}
.ma-content h2 {
color: #2c3e50;
margin-top: 30px;
}
.ma-content h3 {
color: #2c3e50;
margin-top: 20px;
}
@media (max-width: 600px) {
.ma-grid {
grid-template-columns: 1fr;
}
}
function calculateAffordability() {
// Get inputs
var annualIncome = parseFloat(document.getElementById('ma_annual_income').value);
var monthlyDebts = parseFloat(document.getElementById('ma_monthly_debts').value);
var downPayment = parseFloat(document.getElementById('ma_down_payment').value);
var interestRate = parseFloat(document.getElementById('ma_interest_rate').value);
var loanTerm = parseFloat(document.getElementById('ma_loan_term').value);
var taxRate = parseFloat(document.getElementById('ma_tax_rate').value);
var insuranceYearly = parseFloat(document.getElementById('ma_insurance').value);
var dtiLimit = parseFloat(document.getElementById('ma_dti_limit').value);
// Validation
if (isNaN(annualIncome) || annualIncome <= 0) {
alert("Please enter a valid Annual Gross Income.");
return;
}
if (isNaN(monthlyDebts)) monthlyDebts = 0;
if (isNaN(downPayment)) downPayment = 0;
if (isNaN(interestRate) || interestRate <= 0) {
alert("Please enter a valid Interest Rate.");
return;
}
if (isNaN(taxRate)) taxRate = 1.2;
if (isNaN(insuranceYearly)) insuranceYearly = 1000;
// Monthly Income
var monthlyIncome = annualIncome / 12;
// Max Allowable Monthly Payment (Back-end Ratio)
// Total Debts + Housing <= Income * DTI
// Housing <= (Income * DTI) – Other Debts
var maxTotalDebtPayment = monthlyIncome * (dtiLimit / 100);
var maxHousingPayment = maxTotalDebtPayment – monthlyDebts;
if (maxHousingPayment <= 0) {
document.getElementById('ma-result').style.display = 'block';
document.getElementById('ma_result_price').innerText = "$0";
document.getElementById('ma_result_payment').innerText = "Income too low for debts";
document.getElementById('ma_result_pi').innerText = "-";
document.getElementById('ma_result_ti').innerText = "-";
document.getElementById('ma_result_loan').innerText = "-";
return;
}
// Calculation Logic
// MaxHousingPayment = P&I + MonthlyTax + MonthlyInsurance
// MonthlyTax = (HomePrice * (taxRate/100)) / 12
// MonthlyInsurance = insuranceYearly / 12 (Simplified as fixed amount relative to price usually, but user gave fixed $)
// Actually, insurance is often fixed, let's treat it as fixed deduction from ability to pay.
var availableForPITandTax = maxHousingPayment – (insuranceYearly / 12);
if (availableForPITandTax <= 0) {
document.getElementById('ma-result').style.display = 'block';
document.getElementById('ma_result_price').innerText = "$0";
document.getElementById('ma_result_payment').innerText = "Insufficent for Insurance";
return;
}
// Loan Logic
// r = monthly interest rate
// n = total months
var r = (interestRate / 100) / 12;
var n = loanTerm * 12;
// Mortgage Constant (Factor to calculate Monthly P&I from Loan Amount)
// P&I = LoanAmount * ( r(1+r)^n / ((1+r)^n – 1) )
var mortgageFactor = (r * Math.pow(1 + r, n)) / (Math.pow(1 + r, n) – 1);
// The Algebra:
// availableForPITandTax = (LoanAmount * mortgageFactor) + (HomePrice * MonthlyTaxRate)
// LoanAmount = HomePrice – DownPayment
// availableForPITandTax = ((HomePrice – DownPayment) * mortgageFactor) + (HomePrice * MonthlyTaxRate)
// availableForPITandTax = (HomePrice * mortgageFactor) – (DownPayment * mortgageFactor) + (HomePrice * MonthlyTaxRate)
// availableForPITandTax + (DownPayment * mortgageFactor) = HomePrice * (mortgageFactor + MonthlyTaxRate)
// HomePrice = (availableForPITandTax + (DownPayment * mortgageFactor)) / (mortgageFactor + MonthlyTaxRate)
var monthlyTaxRate = (taxRate / 100) / 12;
var maxHomePrice = (availableForPITandTax + (downPayment * mortgageFactor)) / (mortgageFactor + monthlyTaxRate);
// Check if Down Payment exceeds Max Home Price (math quirk if debts are high)
if (maxHomePrice < downPayment) {
// If the math says price < downpayment, it means they can't even afford the taxes on a house they buy with cash.
// But simplified:
maxHomePrice = downPayment;
}
var loanAmount = maxHomePrice – downPayment;
if (loanAmount < 0) loanAmount = 0;
var monthlyPI = loanAmount * mortgageFactor;
var monthlyTax = maxHomePrice * monthlyTaxRate;
var monthlyIns = insuranceYearly / 12;
var totalMonthly = monthlyPI + monthlyTax + monthlyIns;
// Update UI
document.getElementById('ma-result').style.display = 'block';
// Format Currency Function
function formatMoney(num) {
return '$' + num.toFixed(0).replace(/\B(?=(\d{3})+(?!\d))/g, ",");
}
document.getElementById('ma_result_price').innerText = formatMoney(maxHomePrice);
document.getElementById('ma_result_payment').innerText = formatMoney(totalMonthly);
document.getElementById('ma_result_pi').innerText = formatMoney(monthlyPI);
document.getElementById('ma_result_ti').innerText = formatMoney(monthlyTax + monthlyIns);
document.getElementById('ma_result_loan').innerText = formatMoney(loanAmount);
}
Mortgage Affordability Calculator
Your total income before taxes.
Car loans, credit cards, student loans.
Cash available for upfront payment.
30 Years
15 Years
20 Years
10 Years
Annual tax as % of home value.
Conservative (36%)
Standard (43%)
Aggressive (50%)
Debt-to-Income aggressiveness.
Maximum Home Price You Can Afford
$0
Est. Monthly Payment
$0
Principal & Interest
$0
Taxes & Insurance
$0
Loan Amount
$0
How Much House Can You Really Afford?
Determining your home buying budget is the critical first step in the real estate journey. This Mortgage Affordability Calculator goes beyond simple estimates by considering your debt-to-income ratio (DTI), down payment, interest rates, and often-overlooked costs like property taxes and homeowners insurance.
Understanding the 28/36 Rule
Lenders use specific ratios to decide how much money they will lend you. A common standard is the 28/36 rule:
- Front-End Ratio (28%): Your housing costs (mortgage principal, interest, taxes, and insurance) should not exceed 28% of your gross monthly income.
- Back-End Ratio (36%): Your total monthly debt payments (housing + credit cards, car loans, student loans) should not exceed 36% of your gross monthly income.
While some loan programs (like FHA or VA loans) allow for higher ratios (up to 43% or even 50%), staying within the conservative 28/36 range ensures you aren't "house poor."
Key Factors Affecting Your Affordability
Several variables impact your maximum home price:
- Interest Rates: Even a 1% increase in rates can significantly reduce your purchasing power, as more of your monthly payment goes toward interest rather than equity.
- Down Payment: A larger down payment reduces the loan amount, lowers monthly payments, and may eliminate the need for Private Mortgage Insurance (PMI).
- Existing Debt: Reducing monthly obligations like car payments or credit card minimums dollar-for-dollar increases the amount you can allocate toward a mortgage.
- Property Taxes: High-tax areas reduce the amount of mortgage you can afford because taxes are included in the DTI calculation.
How to Improve Your Home Buying Budget
If the calculator result is lower than expected, consider paying down high-interest consumer debt before applying. Alternatively, saving for a larger down payment not only increases your budget but often secures a lower interest rate.