10 Year Fixed Mortgage Rates Mortgage Calculator

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Mortgage Affordability Calculator

30 Years Fixed 20 Years Fixed 15 Years Fixed 10 Years Fixed

Your Buying Power

Estimated Home Price

$0

Max Loan Amount

$0

Monthly P&I Payment

$0

Note: This estimate uses a Debt-to-Income (DTI) ratio of 36%. Depending on your credit score and loan type (FHA vs. Conventional), you may qualify for more or less.

How Much House Can You Actually Afford?

Determining your home buying power is the most critical first step in the real estate journey. While banks often use complex algorithms, the core calculation relies on your Debt-to-Income (DTI) ratio. This ratio compares your gross monthly income against your monthly recurring debts (like car loans, student loans, and credit cards) plus your future mortgage payment.

Key Factors in the Calculation

  • Gross Annual Income: Your total earnings before taxes. Lenders look at consistency over the last two years.
  • The 36% Rule: Most traditional lenders prefer that your total debt payments (including the new mortgage) do not exceed 36% of your gross monthly income.
  • Down Payment: The cash you bring to the table directly increases your purchase price potential without increasing your monthly loan payment.
  • Interest Rates: Even a 1% change in interest rates can shift your buying power by tens of thousands of dollars.

Real-World Example

Suppose a couple earns a combined $100,000 per year. Their monthly gross income is roughly $8,333. At a 36% DTI, their total debt limit is $3,000/month. If they have $500 in existing car and student loan payments, they have $2,500 remaining for their mortgage, taxes, and insurance. With a 7% interest rate and a $50,000 down payment, they could likely afford a home priced around $350,000 to $380,000.

function calculateAffordability() { var annualIncome = parseFloat(document.getElementById('annualIncome').value) || 0; var monthlyDebt = parseFloat(document.getElementById('monthlyDebt').value) || 0; var downPayment = parseFloat(document.getElementById('downPayment').value) || 0; var annualRate = parseFloat(document.getElementById('interestRate').value) || 0; var loanYears = parseInt(document.getElementById('loanTerm').value) || 30; var taxIns = parseFloat(document.getElementById('taxInsurance').value) || 0; if (annualIncome <= 0 || annualRate <= 0) { alert("Please enter valid income and interest rate values."); return; } // 1. Calculate Monthly Gross Income var monthlyGross = annualIncome / 12; // 2. Determine Max Monthly P&I (Using 36% DTI benchmark) // Total Debt Limit = Gross * 0.36 // Max P&I = Total Debt Limit – Current Debt – Taxes/Insurance var totalDebtLimit = monthlyGross * 0.36; var maxMonthlyPI = totalDebtLimit – monthlyDebt – taxIns; if (maxMonthlyPI <= 0) { document.getElementById('results-area').style.display = 'block'; document.getElementById('totalHomePrice').innerText = "$0"; document.getElementById('maxLoanAmount').innerText = "$0"; document.getElementById('monthlyPI').innerText = "$0"; alert("Your current debts and taxes exceed the recommended 36% DTI ratio."); return; } // 3. Solve for Principal (P) using Mortgage Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1] // P = M / ( [ i(1 + i)^n ] / [ (1 + i)^n – 1] ) var monthlyRate = (annualRate / 100) / 12; var numberOfPayments = loanYears * 12; var numerator = monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments); var denominator = Math.pow(1 + monthlyRate, numberOfPayments) – 1; var factor = numerator / denominator; var maxLoan = maxMonthlyPI / factor; var totalHomePrice = maxLoan + downPayment; // Format results var formatter = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD', maximumFractionDigits: 0 }); document.getElementById('totalHomePrice').innerText = formatter.format(totalHomePrice); document.getElementById('maxLoanAmount').innerText = formatter.format(maxLoan); document.getElementById('monthlyPI').innerText = formatter.format(maxMonthlyPI); document.getElementById('results-area').style.display = 'block'; // Smooth scroll to results document.getElementById('results-area').scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

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