.ma-calculator-wrapper {
font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
padding: 20px;
background-color: #ffffff;
border: 1px solid #e0e0e0;
border-radius: 8px;
box-shadow: 0 4px 12px rgba(0,0,0,0.05);
}
.ma-calc-header {
text-align: center;
margin-bottom: 30px;
color: #2c3e50;
}
.ma-calc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.ma-calc-grid {
grid-template-columns: 1fr;
}
}
.ma-input-group {
display: flex;
flex-direction: column;
}
.ma-input-group label {
font-weight: 600;
margin-bottom: 8px;
color: #555;
font-size: 0.95rem;
}
.ma-input-group input, .ma-input-group select {
padding: 12px;
border: 1px solid #ddd;
border-radius: 6px;
font-size: 1rem;
transition: border-color 0.3s;
}
.ma-input-group input:focus {
border-color: #3498db;
outline: none;
}
.ma-btn-container {
grid-column: 1 / -1;
margin-top: 20px;
text-align: center;
}
.ma-calculate-btn {
background-color: #2980b9;
color: white;
border: none;
padding: 15px 40px;
font-size: 1.1rem;
font-weight: bold;
border-radius: 6px;
cursor: pointer;
transition: background-color 0.2s;
}
.ma-calculate-btn:hover {
background-color: #1f6391;
}
.ma-results-section {
grid-column: 1 / -1;
background-color: #f8f9fa;
padding: 25px;
border-radius: 8px;
margin-top: 25px;
border-left: 5px solid #2980b9;
display: none; /* Hidden by default */
}
.ma-result-row {
display: flex;
justify-content: space-between;
align-items: center;
margin-bottom: 15px;
padding-bottom: 15px;
border-bottom: 1px solid #e9ecef;
}
.ma-result-row:last-child {
border-bottom: none;
margin-bottom: 0;
padding-bottom: 0;
}
.ma-result-label {
font-size: 1rem;
color: #666;
}
.ma-result-value {
font-size: 1.4rem;
font-weight: 800;
color: #2c3e50;
}
.ma-highlight {
color: #27ae60;
font-size: 1.8rem;
}
.ma-error-msg {
color: #c0392b;
text-align: center;
grid-column: 1 / -1;
display: none;
font-weight: bold;
}
/* Article Styles */
.ma-article-content {
max-width: 800px;
margin: 40px auto;
font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
line-height: 1.6;
color: #333;
}
.ma-article-content h2 {
color: #2c3e50;
margin-top: 30px;
border-bottom: 2px solid #eee;
padding-bottom: 10px;
}
.ma-article-content h3 {
color: #34495e;
margin-top: 25px;
}
.ma-article-content p {
margin-bottom: 15px;
}
.ma-article-content ul {
margin-bottom: 20px;
padding-left: 20px;
}
.ma-article-content li {
margin-bottom: 8px;
}
function calculateMortgageAffordability() {
// 1. Get Inputs by ID matching exact HTML element IDs
var incomeInput = document.getElementById('grossAnnualIncome').value;
var debtsInput = document.getElementById('monthlyDebts').value;
var downPayInput = document.getElementById('downPayment').value;
var rateInput = document.getElementById('interestRate').value;
var termInput = document.getElementById('loanTerm').value;
var taxInput = document.getElementById('propertyTaxRate').value;
var insInput = document.getElementById('homeInsurance').value;
var dtiMode = document.getElementById('dtiLimit').value;
// 2. Validate and Parse
if (incomeInput === "" || downPayInput === "" || rateInput === "") {
document.getElementById('errorMsg').style.display = 'block';
document.getElementById('resultsSection').style.display = 'none';
return;
}
var grossAnnual = parseFloat(incomeInput);
var monthlyDebt = debtsInput === "" ? 0 : parseFloat(debtsInput);
var downPayment = parseFloat(downPayInput);
var interestRate = parseFloat(rateInput);
var years = parseInt(termInput);
var annualTax = taxInput === "" ? 0 : parseFloat(taxInput);
var annualIns = insInput === "" ? 0 : parseFloat(insInput);
if (isNaN(grossAnnual) || isNaN(downPayment) || isNaN(interestRate)) {
document.getElementById('errorMsg').style.display = 'block';
return;
}
document.getElementById('errorMsg').style.display = 'none';
// 3. Define DTI Ratios based on selection
var frontEndRatio = 0.28;
var backEndRatio = 0.36;
if (dtiMode === 'aggressive') {
frontEndRatio = 0.33;
backEndRatio = 0.43;
} else if (dtiMode === 'conservative') {
frontEndRatio = 0.25;
backEndRatio = 0.33;
}
// 4. Calculate Monthly Income
var grossMonthly = grossAnnual / 12;
// 5. Calculate Allowable Monthly Payments (PITI)
// Rule 1: Front End (Housing costs only)
var maxHousingPaymentFront = grossMonthly * frontEndRatio;
// Rule 2: Back End (Housing + Debts)
var maxTotalPaymentBack = grossMonthly * backEndRatio;
var maxHousingPaymentBack = maxTotalPaymentBack – monthlyDebt;
// Determine which rule limits the borrower
var maxAllowedPITI = 0;
var limitFactor = "";
if (maxHousingPaymentFront < maxHousingPaymentBack) {
maxAllowedPITI = maxHousingPaymentFront;
limitFactor = "Front-End Ratio (Income)";
} else {
maxAllowedPITI = maxHousingPaymentBack;
limitFactor = "Back-End Ratio (Debts)";
}
// Ensure maxAllowedPITI isn't negative (if debts are huge)
if (maxAllowedPITI < 0) maxAllowedPITI = 0;
// 6. Subtract non-mortgage housing costs (Tax + Insurance) to get Max Principal & Interest
var monthlyTaxAndIns = (annualTax + annualIns) / 12;
var maxPandI = maxAllowedPITI – monthlyTaxAndIns;
if (maxPandI < 0) maxPandI = 0;
// 7. Calculate Max Loan Amount using PV formula
// PV = P * (1 – (1+r)^-n) / r
var r = (interestRate / 100) / 12;
var n = years * 12;
var maxLoanAmount = 0;
if (r === 0) {
maxLoanAmount = maxPandI * n;
} else {
maxLoanAmount = maxPandI * (1 – Math.pow(1 + r, -n)) / r;
}
// 8. Calculate Max Home Price
var maxHomePrice = maxLoanAmount + downPayment;
// 9. Formatting Helper
function formatMoney(num) {
return '$' + num.toFixed(0).replace(/(\d)(?=(\d{3})+(?!\d))/g, '$1,');
}
// 10. Display Results
document.getElementById('resMaxPrice').innerText = formatMoney(maxHomePrice);
document.getElementById('resMonthlyPayment').innerText = formatMoney(maxAllowedPITI);
document.getElementById('resLoanAmount').innerText = formatMoney(maxLoanAmount);
document.getElementById('resPandI').innerText = formatMoney(maxPandI);
document.getElementById('resLimitFactor').innerText = limitFactor;
document.getElementById('resultsSection').style.display = 'block';
}
Understanding How Much House You Can Afford
Buying a home is one of the most significant financial decisions you will make. This Mortgage Affordability Calculator helps you determine a realistic budget by analyzing your income, current debts, and the specific terms of a potential mortgage. Unlike simple calculators that only look at salary, this tool incorporates the "28/36 Rule" used by lenders to ensure you don't overextend yourself financially.
The 28/36 Rule Explained
Lenders primarily use two ratios to decide how much money they are willing to lend you. Understanding these can help you improve your chances of approval:
- The Front-End Ratio (28%): This rule states that your monthly housing costs—including mortgage principal, interest, property taxes, and insurance (PITI)—should not exceed 28% of your gross monthly income.
- The Back-End Ratio (36%): This rule looks at your total debt load. It states that your housing costs plus all other monthly recurring debts (student loans, car payments, credit cards) should not exceed 36% of your gross monthly income.
Our calculator automatically compares both ratios and uses the stricter limit to give you a safe affordability estimate. If you have high monthly debts, your affordability will likely be capped by the Back-End ratio.
Factors Affecting Your Buying Power
Several variables play a crucial role in determining your maximum home price:
1. Interest Rates
Even a small fluctuation in interest rates can drastically change your buying power. As rates rise, the portion of your monthly payment going toward interest increases, reducing the amount of principal you can afford to borrow. For example, a 1% increase in rates can reduce your buying power by approximately 10-11%.
2. Down Payment
A larger down payment does two things: it reduces the loan amount you need (lowering monthly payments) and instantly increases the maximum price of the home you can purchase. Furthermore, putting down at least 20% often removes the need for Private Mortgage Insurance (PMI), freeing up more monthly cash flow for the mortgage itself.
3. Property Taxes and Insurance
Many buyers forget to factor in property taxes and homeowners insurance. These costs are usually bundled into your monthly mortgage payment (escrow). In areas with high property taxes, your maximum loan amount will be significantly lower because a larger chunk of your monthly budget goes toward taxes rather than the loan principal.
How to Improve Your Affordability
If the results from the calculator are lower than expected, consider these strategies:
- Pay down high-interest debt: Reducing your monthly debt obligations improves your Back-End DTI ratio.
- Increase your down payment: Saving longer to put more money down directly increases your price ceiling.
- Shop for lower insurance rates: Lowering your estimated annual insurance premium leaves more room for the mortgage payment.
Note: This calculator provides an estimate based on standard lending criteria. Actual loan approval amounts may vary based on credit score, employment history, and specific lender requirements.