What Can We Afford Mortgage Calculator

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What Can We Afford Mortgage Calculator

Mortgage Affordability Calculator

Your total income before taxes.
Includes car loans, student loans, credit cards, etc. (excluding proposed mortgage).
The cash you have available for the down payment.
Current market rates for a mortgage.
15 Years 20 Years 30 Years 40 Years Common terms are 15 or 30 years.
Estimate based on your target location (e.g., 1.2% means $1200 per $100,000 value).
Estimated annual cost for homeowner's insurance.
Private Mortgage Insurance, often required if down payment is less than 20%.

Your Affordability Insights

$0 Estimated Maximum Home Price

Max Monthly P&I Payment: $0.00

Estimated Annual Income for Loan: $0.00

Debt-to-Income Ratio (DTI): 0%

How We Calculate Affordability

This calculator estimates your maximum affordable home price based on common lending guidelines (generally aiming for a 28% front-end DTI for P&I and a 36% back-end DTI including all debts). It considers your income, existing debts, down payment, interest rates, and property costs.

  • Front-End DTI (Housing): (Principal + Interest + Taxes + Insurance + PMI) / Gross Monthly Income ≤ 28%
  • Back-End DTI (Total Debt): (Proposed Housing Payment + All Other Monthly Debts) / Gross Monthly Income ≤ 36%
  • The calculator iteratively finds the highest loan amount that satisfies both DTI ratios, then adds your down payment to get the maximum home price.

Breakdown of Estimated Monthly Housing Costs

What is a "What Can We Afford Mortgage Calculator"?

A "What Can We Afford Mortgage Calculator," often referred to as a mortgage affordability calculator or home affordability calculator, is an indispensable online tool designed to help prospective homebuyers understand their potential borrowing capacity and the maximum home price they can realistically afford. It takes into account various financial factors beyond just the loan amount, providing a more holistic picture of homeownership costs. Understanding what you can afford is a crucial first step in the mortgage pre-approval process, preventing you from falling in love with a home outside your financial reach or, conversely, underestimating your true buying power.

Who should use it: Anyone considering purchasing a home, whether it's their first property or a subsequent move. It's particularly useful for individuals or couples who want to get a ballpark figure before speaking with a lender, helping them set realistic expectations and budget accordingly. First-time homebuyers especially benefit from this tool as it demystifies the complex calculations lenders use.

Common misconceptions:

  • It provides a definitive loan approval: This calculator offers an estimate. Only a lender can provide official pre-approval based on a full credit and financial review.
  • It only considers the loan amount: A true affordability calculator includes all associated housing costs like property taxes, insurance, and potentially PMI, giving a more accurate monthly payment picture.
  • It's based solely on income: While income is a primary factor, existing debt obligations, credit score (implicitly through interest rates), and down payment significantly influence affordability. Ignoring these leads to inaccurate "what can we afford" figures.

"What Can We Afford Mortgage Calculator" Formula and Mathematical Explanation

The core of a "What Can We Afford Mortgage Calculator" lies in simulating the lending criteria banks and mortgage providers use. Lenders typically assess affordability using two main Debt-to-Income (DTI) ratios: the front-end DTI (housing expenses) and the back-end DTI (total debt obligations).

Step-by-step derivation:

  1. Calculate Gross Monthly Income (GMI): GMI = Gross Annual Income / 12.
  2. Determine Maximum Allowable Housing Payment (Front-End DTI): Lenders often cap PITI (Principal, Interest, Taxes, Insurance) + PMI at around 28% of GMI. Let's call this PITI_Max.
    PITI_Max = GMI * Front_End_DTI_Limit (e.g., 0.28)
  3. Determine Maximum Allowable Total Debt Payment (Back-End DTI): Lenders typically cap total monthly debt payments (PITI + PMI + Other Debts) at around 36% of GMI. Let's call this TotalDebt_Max.
    TotalDebt_Max = GMI * Back_End_DTI_Limit (e.g., 0.36)
  4. Calculate Maximum Other Monthly Debt: This is the sum of your non-housing monthly debt payments (credit cards, auto loans, student loans, etc.).
    OtherMonthlyDebt = Total Monthly Debt Payments (input)
  5. Calculate Maximum Allowable Principal & Interest (P&I) Payment: The portion of the PITI payment available for P&I is crucial.
    Max_PI_Payment = MIN( PITI_Max – MonthlyTaxes – MonthlyInsurance – MonthlyPMI , TotalDebt_Max – OtherMonthlyDebt – MonthlyTaxes – MonthlyInsurance – MonthlyPMI )
    Note: MonthlyTaxes, MonthlyInsurance, and MonthlyPMI are calculated from annual figures: (Annual Property Tax / 12), (Annual Home Insurance / 12), (Annual PMI / 12). If PMI rate is 0, MonthlyPMI is 0.
  6. Calculate Maximum Loan Amount: Using the standard mortgage payment formula (M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]), we solve for P (Principal/Loan Amount).
    M = Max_PI_Payment
    i = Monthly Interest Rate (Annual Rate / 12 / 100)
    n = Loan Term in Months (Loan Term in Years * 12)
    The formula rearranged for P is:
    P = M * [ (1 + i)^n – 1 ] / [ i(1 + i)^n ]
  7. Calculate Maximum Home Price: This is the maximum loan amount plus the down payment.
    MaxHomePrice = P + Down Payment

Variable Explanations:

Variable Name Meaning Unit Typical Range
Gross Annual Income (GAI) Total income before taxes and deductions. Currency (e.g., USD) $40,000 – $500,000+
Gross Monthly Income (GMI) GAI divided by 12. Currency (e.g., USD) $3,333 – $41,667+
Total Monthly Debt Payments Sum of minimum monthly payments for credit cards, auto loans, student loans, personal loans, etc. (Excludes proposed mortgage). Currency (e.g., USD) $0 – $5,000+
Down Payment Cash paid upfront towards the home purchase. Currency (e.g., USD) $0 – 50%+ of home price
Estimated Mortgage Interest Rate Annual interest rate for the mortgage loan. Percentage (%) 3.0% – 10.0%+
Mortgage Loan Term Duration of the mortgage loan. Years 15, 20, 30, 40
Annual Property Tax Rate Percentage of home's assessed value paid annually in property taxes. Percentage (%) 0.5% – 3.0%+
Annual Homeowner's Insurance Estimated yearly cost for property insurance. Currency (e.g., USD) $600 – $3,000+
Annual PMI Rate Percentage of loan amount paid annually for Private Mortgage Insurance. Percentage (%) 0% – 1.5%
Front-End DTI Limit Maximum allowable percentage of GMI for housing costs (PITI+PMI). Percentage (%) Typically 25% – 35% (often 28%)
Back-End DTI Limit Maximum allowable percentage of GMI for total debt payments. Percentage (%) Typically 35% – 45% (often 36%)
Maximum P&I Payment The highest affordable monthly payment for principal and interest only. Currency (e.g., USD) Calculated
Maximum Loan Amount The total amount that can be borrowed for the mortgage. Currency (e.g., USD) Calculated
Maximum Home Price Maximum Loan Amount + Down Payment. Currency (e.g., USD) Calculated

Practical Examples (Real-World Use Cases)

Let's explore how the "What Can We Afford Mortgage Calculator" works with realistic scenarios. These examples demonstrate how different financial profiles lead to varying affordability estimates, highlighting the importance of each input parameter in determining your home buying power.

Example 1: Young Professional Couple Saving for First Home

Scenario: Sarah and Ben, a couple earning a combined gross annual income, are looking to buy their first home. They have a modest amount saved for a down payment and some existing student loan debt.

Input Values:

  • Gross Annual Income: $120,000
  • Total Monthly Debt Payments: $500 (student loans)
  • Down Payment Amount: $30,000
  • Estimated Mortgage Interest Rate: 6.75%
  • Mortgage Loan Term: 30 Years
  • Annual Property Tax Rate: 1.1%
  • Annual Homeowner's Insurance: $1,500
  • Annual PMI Rate: 0.6% (assuming less than 20% down)

Calculator Output:

  • Estimated Maximum Home Price: $450,000 (approximate)
  • Max Monthly P&I Payment: $2,340 (approximate)
  • Estimated Annual Income for Loan: $70,800 (based on 28% front-end DTI for PITI)
  • Debt-to-Income Ratio (DTI): 31% (calculated back-end DTI)

Financial Interpretation:

Based on their income, debts, and desired housing costs, Sarah and Ben can likely afford a home priced around $450,000. Their maximum monthly principal and interest (P&I) payment would be approximately $2,340. The calculation indicates they'd need to qualify for a loan where the total housing expenses (PITI + PMI) don't exceed about $2,800 per month (28% of their $10,000 gross monthly income). Their total debt obligations, including this estimated housing payment and their existing student loans, would remain below the 36% back-end DTI threshold. This estimate empowers them to search within a specific price range, making their home search more focused.

Example 2: Established Family Upgrading Home

Scenario: The Miller family is looking to upgrade to a larger home. They have a higher combined income, significant savings for a down payment, and manageable existing debts.

Input Values:

  • Gross Annual Income: $250,000
  • Total Monthly Debt Payments: $1,200 (car payment, credit card)
  • Down Payment Amount: $100,000
  • Estimated Mortgage Interest Rate: 6.5%
  • Mortgage Loan Term: 30 Years
  • Annual Property Tax Rate: 1.3%
  • Annual Homeowner's Insurance: $2,000
  • Annual PMI Rate: 0% (assuming >20% down)

Calculator Output:

  • Estimated Maximum Home Price: $985,000 (approximate)
  • Max Monthly P&I Payment: $5,150 (approximate)
  • Estimated Annual Income for Loan: $151,667 (based on 28% front-end DTI for PITI)
  • Debt-to-Income Ratio (DTI): 29% (calculated back-end DTI)

Financial Interpretation:

The Millers' stronger financial position allows for significantly higher affordability. With a $100,000 down payment and considering their income and debts, they could potentially afford a home priced near $985,000. Their maximum P&I payment could be around $5,150 per month. Their total monthly housing expenses (PITI, as PMI is 0) would be roughly $4,000 (28% of their $20,833 gross monthly income), well within limits. Crucially, their total debt obligations, including this potential mortgage, would fall under a 36% DTI ratio, indicating they are likely to qualify for a larger loan. This calculation helps them target homes in a higher price bracket, making their real estate market analysis more relevant.

How to Use This "What Can We Afford Mortgage Calculator"

Using this "What Can We Afford Mortgage Calculator" is straightforward and provides valuable insights for your home-buying journey. Follow these simple steps to get your personalized affordability estimate.

Step-by-step instructions:

  1. Input Your Financial Data: Enter your Gross Annual Income, Total Monthly Debt Payments (excluding any potential mortgage), and your available Down Payment Amount.
  2. Provide Loan & Property Details: Input the Estimated Mortgage Interest Rate you expect, select your preferred Mortgage Loan Term (e.g., 15, 30 years), estimate your Annual Property Tax Rate, Annual Homeowner's Insurance cost, and the Annual PMI Rate if applicable (often required if your down payment is less than 20% of the home price).
  3. Click Calculate: Once all fields are populated, click the "Calculate" button.
  4. Review Your Results: The calculator will display:
    • Estimated Maximum Home Price: This is the most crucial figure, indicating the highest price point you can likely afford.
    • Max Monthly P&I Payment: The maximum monthly payment for Principal and Interest alone that fits lending guidelines.
    • Estimated Annual Income for Loan: Shows the income level required to support the calculated housing payment based on a typical front-end DTI ratio.
    • Debt-to-Income Ratio (DTI): Your overall DTI, combining estimated housing costs with existing debts. Lenders use this heavily.
  5. Interpret the Data: Use the "Max Monthly P&I Payment" and "Estimated Maximum Home Price" to guide your home search. Ensure the total monthly housing cost (P&I + Taxes + Insurance + PMI) fits comfortably within your budget and doesn't exceed typical lender limits (like the 28% front-end DTI). Check that your total debt obligations (including the estimated housing payment) stay within the common 36% back-end DTI limit.
  6. Refine and Adjust: If the results aren't what you expected, try adjusting inputs like the down payment, interest rate assumptions, or even your target home price range. Consider how reducing debt or increasing income could impact your affordability.
  7. Use the "Copy Results" Button: Easily copy a summary of your key results for notes or to share.
  8. Reset: Use the "Reset" button to clear all fields and start fresh.

How to interpret results:

The primary result, "Estimated Maximum Home Price," is a strong indicator but not a guarantee. It's derived from lender guidelines and your inputs. A lower DTI ratio generally indicates stronger financial health and potentially better loan terms. The breakdown helps you understand the components of your monthly housing payment and how your existing debts factor in. Remember that lender approval depends on your credit score, employment history, and other underwriting factors not included in this calculator.

Decision-making guidance:

Use these figures to confidently set your home search parameters. If your calculated affordability is lower than expected, consider strategies like saving a larger down payment, paying down existing debts, or exploring different loan programs. If it's higher, you may have room to increase your budget or focus on properties with lower ongoing costs. This tool is a fantastic starting point for a mortgage consultation.

Key Factors That Affect "What Can We Afford Mortgage Calculator" Results

Several critical financial elements significantly influence the outcome of any "What Can We Afford Mortgage Calculator." Understanding these factors allows you to better interpret the results and strategize your home-buying approach.

  • Gross Income: This is the foundational input. Higher gross income directly increases borrowing potential, as it allows for higher monthly payments within the DTI limits.
  • Existing Debts: Every monthly debt payment (car loans, student loans, credit cards, personal loans) reduces the amount of income available for a mortgage payment. Lowering these debts before applying for a mortgage can substantially increase your affordability.
  • Down Payment Size: A larger down payment directly reduces the loan amount needed, thus lowering the required monthly P&I payment and potentially increasing the maximum home price you can afford. It also helps avoid PMI.
  • Interest Rate: Even a small change in the mortgage interest rate has a large impact. A higher rate means a larger portion of your monthly payment goes towards interest, reducing the principal you can borrow for the same monthly payment. This is why shopping for the best mortgage rates is vital.
  • Loan Term: Longer loan terms (e.g., 30 years vs. 15 years) result in lower monthly payments for the same loan amount, potentially increasing the maximum loan size. However, you'll pay significantly more interest over the life of the loan.
  • Property Taxes and Homeowner's Insurance: These are mandatory costs that are included in your monthly housing payment (PITI). Higher property taxes or insurance premiums in a specific area will decrease your affordability for a given price point.
  • Private Mortgage Insurance (PMI): If your down payment is less than 20%, PMI is typically required. This adds to your monthly housing cost, reducing the principal you can afford for the same total monthly payment.
  • Credit Score: While not a direct input in most simple calculators, your credit score heavily influences the interest rate you'll be offered. A lower credit score usually means a higher interest rate, significantly impacting affordability.
  • Lender Overlays: While standard DTI ratios are common, individual lenders may have stricter internal guidelines ("overlays") that can further limit borrowing capacity.

Frequently Asked Questions (FAQ)

Q1: How accurate is a "What Can We Afford Mortgage Calculator"?
These calculators provide excellent estimates based on common lending formulas. However, they are not official loan approvals. Your actual borrowing capacity will be determined by a lender after a full review of your credit report, income verification, assets, and other underwriting criteria. Lender overlays can also affect final approval amounts.
Q2: What DTI ratio do lenders typically use?
Most lenders look at two main DTI ratios: the front-end ratio (housing costs only, typically capped around 28-31% of gross monthly income) and the back-end ratio (all debts including housing, typically capped around 36-45% of gross monthly income). These figures can vary based on the loan type, lender, and borrower's overall financial profile.
Q3: Should I aim for the maximum I can afford?
Not necessarily. While the calculator shows your maximum borrowing power, it's wise to consider a comfortable monthly payment that fits your lifestyle and budget, leaving room for savings, unexpected expenses, and discretionary spending. Being "house poor" can be financially and emotionally stressful.
Q4: How does a large down payment affect affordability?
A larger down payment significantly increases affordability. It reduces the loan principal needed, lowers the monthly payment (P&I), helps avoid Private Mortgage Insurance (PMI), and may even qualify you for better interest rates.
Q5: What if my income is variable (e.g., self-employed, commission-based)?
If your income is variable, lenders will typically average your income over the past 1-2 years (or more) and may require additional documentation. For calculators, use a conservative average of your gross income. It's best to consult directly with a mortgage lender for precise figures.
Q6: Does the calculator include closing costs?
This specific "What Can We Afford Mortgage Calculator" focuses on the maximum home price based on loan qualification. It does not directly calculate or include closing costs (like appraisal fees, title insurance, origination fees). Buyers need to budget separately for these, which can range from 2-5% of the loan amount.
Q7: How important is the loan term (15 vs. 30 years)?
A shorter loan term (e.g., 15 years) results in higher monthly payments but significantly less interest paid over the life of the loan, building equity faster. A longer term (e.g., 30 years) means lower monthly payments, potentially allowing you to borrow more or simply making the payment more manageable, but at the cost of more total interest paid.
Q8: Can this calculator estimate my total monthly housing payment (PITI)?
Yes, while the primary result is the maximum home price, the intermediate results and the formula explanation help you understand the components. By taking the estimated maximum loan amount derived from the Max Monthly P&I Payment, and adding the calculated monthly taxes, insurance, and PMI, you can approximate your total PITI payment. Many lenders will use a similar calculation to ensure it aligns with their DTI limits.
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Related Tools and Internal Resources

var annualIncomeInput = document.getElementById("annualIncome"); var monthlyDebtInput = document.getElementById("monthlyDebt"); var downPaymentInput = document.getElementById("downPayment"); var interestRateInput = document.getElementById("interestRate"); var loanTermInput = document.getElementById("loanTerm"); var propertyTaxRateInput = document.getElementById("propertyTaxRate"); var homeInsuranceInput = document.getElementById("homeInsurance"); var pmiRateInput = document.getElementById("pmiRate"); var annualIncomeError = document.getElementById("annualIncomeError"); var monthlyDebtError = document.getElementById("monthlyDebtError"); var downPaymentError = document.getElementById("downPaymentError"); var interestRateError = document.getElementById("interestRateError"); var propertyTaxRateError = document.getElementById("propertyTaxRateError"); var homeInsuranceError = document.getElementById("homeInsuranceError"); var pmiRateError = document.getElementById("pmiRateError"); var maxHomePriceDisplay = document.querySelector('.main-result span'); var maxMonthlyPIDisplay = document.getElementById("maxMonthlyPI"); var annualIncomeForLoanDisplay = document.getElementById("annualIncomeForLoan"); var dtiRatioDisplay = document.getElementById("dtiRatio"); var chart = null; var chartCtx = document.getElementById("affordabilityChart").getContext("2d"); function formatCurrency(amount) { return "$" + amount.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,'); } function formatPercent(percent) { return (percent * 100).toFixed(2) + "%"; } function showError(element, message) { if (element) { element.textContent = message; element.style.display = 'block'; } } function clearError(element) { if (element) { element.textContent = "; element.style.display = 'none'; } } function isValidNumber(value) { return !isNaN(parseFloat(value)) && isFinite(value); } function calculateAffordability() { // Clear previous errors clearError(annualIncomeError); clearError(monthlyDebtError); clearError(downPaymentError); clearError(interestRateError); clearError(propertyTaxRateError); clearError(homeInsuranceError); clearError(pmiRateError); // Get input values var annualIncome = parseFloat(annualIncomeInput.value); var monthlyDebt = parseFloat(monthlyDebtInput.value); var downPayment = parseFloat(downPaymentInput.value); var interestRate = parseFloat(interestRateInput.value); var loanTerm = parseInt(loanTermInput.value); var propertyTaxRate = parseFloat(propertyTaxRateInput.value); var homeInsurance = parseFloat(homeInsuranceInput.value); var pmiRate = parseFloat(pmiRateInput.value); // Input validation var errors = false; if (!isValidNumber(annualIncome) || annualIncome <= 0) { showError(annualIncomeError, "Please enter a valid gross annual income."); errors = true; } if (!isValidNumber(monthlyDebt) || monthlyDebt < 0) { showError(monthlyDebtError, "Please enter a valid monthly debt amount (0 or more)."); errors = true; } if (!isValidNumber(downPayment) || downPayment < 0) { showError(downPaymentError, "Please enter a valid down payment amount (0 or more)."); errors = true; } if (!isValidNumber(interestRate) || interestRate <= 0) { showError(interestRateError, "Please enter a valid interest rate (e.g., 6.5)."); errors = true; } if (!isValidNumber(propertyTaxRate) || propertyTaxRate < 0) { showError(propertyTaxRateError, "Please enter a valid property tax rate (e.g., 1.2)."); errors = true; } if (!isValidNumber(homeInsurance) || homeInsurance < 0) { showError(homeInsuranceError, "Please enter a valid home insurance amount (0 or more)."); errors = true; } if (!isValidNumber(pmiRate) || pmiRate < 0) { showError(pmiRateError, "Please enter a valid PMI rate (e.g., 0.5)."); errors = true; } if (errors) { updateResults(0, 0, 0, 0); // Reset results if validation fails return; } var grossMonthlyIncome = annualIncome / 12; var monthlyPropertyTax = (propertyTaxRate / 100) * (100000 / 100); // Placeholder for tax per 100k value – we'll need to estimate based on potential price later var monthlyHomeInsurance = homeInsurance / 12; var monthlyPMI = (pmiRate / 100) * (100000 / 100); // Placeholder for PMI per 100k loan – estimate needed // Lender Ratios (common benchmarks) var frontEndDTILimit = 0.28; // For PITI + PMI var backEndDTILimit = 0.36; // For PITI + PMI + Other Debts var maxHousingPaymentBudget = grossMonthlyIncome * frontEndDTILimit; var maxTotalDebtPaymentBudget = grossMonthlyIncome * backEndDTILimit; var maxOtherMonthlyDebt = monthlyDebt; var maxAffordableLoan = 0; var estimatedMaxHomePrice = 0; var maxMonthlyPI = 0; var estimatedAnnualIncomeForLoan = grossMonthlyIncome * frontEndDTILimit; // This is a simplified view, actual loan requires calculation // Iterative approach to find max loan amount // We need to estimate property value to calculate taxes/PMI properly, then adjust. // Start with a rough estimate, e.g., based on income. var currentEstimatedHomePrice = grossMonthlyIncome * 12 * 3; // Rough initial estimate var maxIterations = 100; var tolerance = 0.01; // Small tolerance for convergence for (var i = 0; i 80% // Calculate potential loan amount for this price first var potentialLoanAmount = currentEstimatedHomePrice – downPayment; if (potentialLoanAmount > 0 && (potentialLoanAmount / currentEstimatedHomePrice) > 0.80) { currentMonthlyPMI = (pmiRate / 100) * (potentialLoanAmount / 100); } var totalMonthlyHousingCosts = currentMonthlyPropertyTax + monthlyHomeInsurance + currentMonthlyPMI; // Calculate remaining budget for Principal & Interest (P&I) var availableForPI = Math.min( maxHousingPaymentBudget – totalMonthlyHousingCosts, maxTotalDebtPaymentBudget – maxOtherMonthlyDebt – totalMonthlyHousingCosts ); if (availableForPI 0) { calculatedLoanAmount = availableForPI * (Math.pow(1 + monthlyInterestRate, loanTermMonths) – 1) / (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, loanTermMonths)); } else { // Handle 0% interest rate edge case calculatedLoanAmount = availableForPI * loanTermMonths; } var nextEstimatedHomePrice = calculatedLoanAmount + downPayment; // Check for convergence if (Math.abs(nextEstimatedHomePrice – currentEstimatedHomePrice) < tolerance) { estimatedMaxHomePrice = nextEstimatedHomePrice; maxAffordableLoan = calculatedLoanAmount; maxMonthlyPI = availableForPI; // This is the P&I part of the budget break; } currentEstimatedHomePrice = nextEstimatedHomePrice; // Prevent infinite loops if no convergence / invalid state if (i === maxIterations – 1) { estimatedMaxHomePrice = currentEstimatedHomePrice; // Best guess maxAffordableLoan = currentEstimatedHomePrice – downPayment; maxMonthlyPI = availableForPI; } } // Final checks and calculations if (estimatedMaxHomePrice < 0) estimatedMaxHomePrice = 0; if (maxAffordableLoan < 0) maxAffordableLoan = 0; if (maxMonthlyPI 0.80 && estimatedMaxHomePrice > 0) { finalMonthlyPMI = (pmiRate / 100) * (maxAffordableLoan / 100); } var finalTotalHousingCosts = finalMonthlyPropertyTax + monthlyHomeInsurance + finalMonthlyPMI; var finalPI = maxMonthlyPI; // The P&I calculated during iteration should represent the max P&I var totalMonthlyObligations = finalPI + finalTotalHousingCosts + maxOtherMonthlyDebt; var finalDTI = (grossMonthlyIncome > 0) ? (totalMonthlyObligations / grossMonthlyIncome) : 0; // Update displays updateResults(estimatedMaxHomePrice, finalPI, grossMonthlyIncome * frontEndDTILimit, finalDTI); updateChart(finalPI, finalTotalHousingCosts); } function updateResults(maxHomePrice, maxPI, incomeForLoan, dti) { maxHomePriceDisplay.textContent = formatCurrency(maxHomePrice); maxMonthlyPIDisplay.textContent = formatCurrency(maxPI); annualIncomeForLoanDisplay.textContent = formatCurrency(incomeForLoan); dtiRatioDisplay.textContent = formatPercent(dti); } function updateChart(principalInterest, otherHousingCosts) { var ctx = document.getElementById("affordabilityChart").getContext("2d"); // Destroy previous chart instance if it exists if (window.chartInstance) { window.chartInstance.destroy(); } // Prepare data for the chart var labels = ['Principal & Interest', 'Taxes, Insurance, PMI']; var dataValues = [principalInterest, otherHousingCosts]; // Ensure no negative values are plotted dataValues[0] = Math.max(0, dataValues[0]); dataValues[1] = Math.max(0, dataValues[1]); var totalMonthlyHousing = dataValues[0] + dataValues[1]; window.chartInstance = new Chart(ctx, { type: 'pie', data: { labels: labels, datasets: [{ data: dataValues, backgroundColor: [ 'rgba(0, 74, 153, 0.7)', // Primary Color for P&I 'rgba(40, 167, 69, 0.7)' // Success Color for Others ], borderColor: '#ffffff', borderWidth: 1 }] }, options: { responsive: true, maintainAspectRatio: false, plugins: { legend: { position: 'bottom', }, title: { display: true, text: `Total Estimated Monthly Housing: ${formatCurrency(totalMonthlyHousing)}`, font: { size: 14, weight: 'bold' }, color: 'var(–primary-color)' }, tooltip: { callbacks: { label: function(context) { var label = context.label || "; if (label) { label += ': '; } if (context.parsed !== null) { label += formatCurrency(context.parsed); } return label; } } } } } }); } function resetCalculator() { annualIncomeInput.value = "; monthlyDebtInput.value = "; downPaymentInput.value = "; interestRateInput.value = "; loanTermInput.value = '30'; propertyTaxRateInput.value = "; homeInsuranceInput.value = "; pmiRateInput.value = "; // Clear errors clearError(annualIncomeError); clearError(monthlyDebtError); clearError(downPaymentError); clearError(interestRateError); clearError(propertyTaxRateError); clearError(homeInsuranceError); clearError(pmiRateError); // Reset results display updateResults(0, 0, 0, 0); updateChart(0, 0); // Clear chart } function copyResults() { var maxHomePrice = maxHomePriceDisplay.textContent; var maxMonthlyPI = maxMonthlyPIDisplay.textContent; var annualIncomeForLoan = annualIncomeForLoanDisplay.textContent; var dtiRatio = dtiRatioDisplay.textContent; var summary = `— Affordability Calculator Results —\n\n` + `Estimated Maximum Home Price: ${maxHomePrice}\n` + `Max Monthly P&I Payment: ${maxMonthlyPI}\n` + `Estimated Annual Income for Loan: ${annualIncomeForLoan}\n` + `Debt-to-Income Ratio (DTI): ${dtiRatio}\n\n` + `Generated using the "What Can We Afford Mortgage Calculator".`; var textArea = document.createElement("textarea"); textArea.value = summary; document.body.appendChild(textArea); textArea.select(); try { document.execCommand('copy'); alert("Results copied to clipboard!"); } catch (err) { console.error('Unable to copy results. Please copy manually.', err); alert("Failed to copy results. Please copy manually."); } finally { document.body.removeChild(textArea); } } // Initial calculation on load (optional, or just rely on user input) // calculateAffordability(); // Add event listeners for real-time updates (optional, but good UX) var inputs = [ annualIncomeInput, monthlyDebtInput, downPaymentInput, interestRateInput, loanTermInput, propertyTaxRateInput, homeInsuranceInput, pmiRateInput ]; inputs.forEach(function(input) { input.addEventListener('input', calculateAffordability); }); // Initial chart setup updateChart(0, 0); // Initialize with empty chart // Initial calculation if fields are pre-filled or for default values // calculateAffordability();

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