Biweekly vs Monthly Mortgage Calculator

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Biweekly vs. Monthly Mortgage Calculator

See how making half payments every two weeks can significantly reduce your mortgage term and total interest paid compared to traditional monthly payments.

Mortgage Payment Comparison

Comparison Results

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Monthly: Total Interest
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Biweekly: Total Interest
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Monthly: Payoff Time
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Biweekly: Payoff Time
How it works:

The biweekly method makes 26 half-payments per year, which equals 13 full monthly payments (instead of 12). This extra payment annually goes directly towards the principal, saving interest and shortening the loan term. Calculations are based on standard amortization formulas.

Results copied to clipboard!

Payment Schedule Comparison

Amortization Overview (First 5 Years)
Year Payment Type Total Paid Total Interest Paid Principal Paid Remaining Balance

What is a Biweekly vs. Monthly Mortgage Payment?

A biweekly vs monthly mortgage payment comparison highlights a strategic approach to mortgage repayment. Traditionally, homeowners make one mortgage payment per month. With a biweekly mortgage payment plan, you essentially pay half of your monthly mortgage payment every two weeks. Since there are 52 weeks in a year, this results in 26 half-payments, which equates to 13 full monthly payments annually (26/2 = 13), rather than the standard 12. This extra payment goes directly towards reducing your principal balance, leading to significant savings in interest and a shorter loan term. Understanding the biweekly vs monthly mortgage calculator is crucial for homeowners looking to optimize their mortgage payments.

This strategy is particularly beneficial for those who can comfortably manage the slightly more frequent payments and want to accelerate their debt payoff. It's a common misconception that biweekly payments require a significant financial strain; in reality, the difference is often spread out in a way that feels manageable. Many lenders offer formal biweekly payment programs, or you can implement it yourself by making an additional principal payment equivalent to half your monthly payment once a year.

The primary users of this strategy are homeowners who aim to:

  • Build equity faster.
  • Reduce the total interest paid over the life of the loan.
  • Pay off their mortgage before the scheduled term.
  • Gain financial freedom sooner.

A key aspect to consider is how lenders report payments. Some lenders automatically enroll you in a biweekly plan that applies your extra payments correctly. Others might simply hold the extra payment until the next full payment is due. It's vital to ensure your lender applies the extra funds directly to the principal. Our biweekly vs monthly mortgage calculator helps you visualize these differences clearly.

Biweekly vs. Monthly Mortgage Payment Formula and Mathematical Explanation

The core of the biweekly vs monthly mortgage calculator lies in understanding mortgage amortization. The monthly payment (M) is calculated using the standard formula:

M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]

Where:

  • P = Principal loan amount
  • i = Monthly interest rate (annual rate / 12)
  • n = Total number of payments (loan term in years * 12)

For a monthly payment plan, you make 'M' payments for 'n' months.

For a biweekly payment plan, the calculation is slightly different. The homeowner pays M/2 every two weeks. Over a year, this totals (M/2) * 26 = M * 13. This effectively means one extra monthly payment is made each year.

The true benefit of the biweekly plan is how this extra annual payment (M) is applied. When paid directly to the principal, it reduces the outstanding balance faster than the standard monthly schedule allows. This leads to less interest accruing over time because interest is calculated on a declining principal balance.

Impact on Total Interest and Payoff Time:

The calculation of total interest paid and the payoff time involves simulating the amortization schedule month by month (or payment by payment). For the monthly plan, the balance decreases according to the standard amortization schedule. For the biweekly plan, the balance decreases at an accelerated rate due to the extra principal payments made twice a month. This reduction in principal means fewer interest charges accrue, and the loan is paid off in fewer total payments than the original term (n).

Our biweekly vs monthly mortgage calculator simulates these schedules to accurately reflect the total interest saved and the reduction in loan term.

Variables Table:

Variable Meaning Unit Typical Range
P (Principal Loan Amount) The total amount borrowed for the mortgage. Currency ($) $100,000 – $1,000,000+
r (Annual Interest Rate) The yearly interest rate charged on the loan. Percentage (%) 2% – 10%+
t (Loan Term) The total duration of the loan in years. Years 15, 20, 30
i (Monthly Interest Rate) The interest rate applied per month. (r / 100) / 12 Decimal 0.00167 – 0.00833
n (Total Payments – Monthly) The total number of monthly payments over the loan term. t * 12 Number 180, 240, 360
M (Monthly Payment) The fixed amount paid each month, covering principal and interest. Currency ($) Varies based on P, r, t
Biweekly Payment Half of the monthly payment, paid every two weeks. (M / 2) Currency ($) Varies
Total Annual Payments (Biweekly) Number of biweekly payments * Biweekly Payment. (26 * M/2 = M*13) Currency ($) M * 13

Practical Examples: Biweekly vs. Monthly Mortgage

Let's illustrate the power of the biweekly vs monthly mortgage calculator with real-world scenarios.

Example 1: First-Time Homebuyer

Scenario: Sarah is buying her first home and secures a mortgage with the following terms:

  • Loan Amount: $350,000
  • Annual Interest Rate: 6.5%
  • Loan Term: 30 Years

Using the Calculator:

Monthly Payment Plan:

  • Estimated Monthly Payment: $2,211.12
  • Total Paid Over 30 Years: $795,999.99
  • Total Interest Paid: $445,999.99
  • Payoff Time: 30 Years

Biweekly Payment Plan:

  • Estimated Half-Biweekly Payment: $1,105.56
  • Total Paid Over Approx. 25.5 Years: $705,233.71
  • Total Interest Paid: $355,233.71
  • Payoff Time: Approx. 25 Years and 6 Months

Financial Interpretation: By opting for the biweekly payment plan, Sarah can save approximately $90,766.28 in interest and pay off her mortgage nearly 4.5 years sooner. This demonstrates a significant advantage of the biweekly vs monthly mortgage strategy.

Example 2: Refinancing a Mortgage

Scenario: John refinanced his existing mortgage and has the following details:

  • Remaining Loan Balance: $250,000
  • Current Annual Interest Rate: 4.0%
  • Remaining Loan Term: 20 Years

Using the Calculator:

Monthly Payment Plan:

  • Estimated Monthly Payment: $1,491.77
  • Total Paid Over 20 Years: $358,024.80
  • Total Interest Paid: $108,024.80
  • Payoff Time: 20 Years

Biweekly Payment Plan:

  • Estimated Half-Biweekly Payment: $745.89
  • Total Paid Over Approx. 17 Years: $307,188.70
  • Total Interest Paid: $57,188.70
  • Payoff Time: Approx. 17 Years

Financial Interpretation: For John, switching to a biweekly payment plan on his remaining balance could save him around $50,836.10 in interest and allow him to become mortgage-free about 3 years earlier. This is a powerful illustration of how consistent extra payments, facilitated by a biweekly schedule, impact long-term mortgage costs.

How to Use This Biweekly vs. Monthly Mortgage Calculator

Our biweekly vs monthly mortgage calculator is designed for simplicity and clarity. Follow these steps to get accurate comparisons:

  1. Enter Loan Amount: Input the total principal amount of your mortgage loan. This is the original amount you borrowed, not including interest.
  2. Enter Annual Interest Rate: Provide the annual interest rate for your mortgage. Ensure you use the percentage (e.g., 5 for 5%, 6.75 for 6.75%).
  3. Enter Loan Term (Years): Specify the original duration of your mortgage loan in years (e.g., 15, 30).
  4. Click 'Calculate': Once all fields are filled, click the "Calculate" button. The calculator will immediately display the comparison results.

How to Read the Results:

  • Main Highlighted Result: This shows the total interest savings achieved by using the biweekly payment method over the life of the loan compared to the monthly method.
  • Intermediate Values: These provide key figures for both payment schedules:
    • Total Interest Paid (Monthly/Biweekly): The cumulative interest you'll pay.
    • Payoff Time (Monthly/Biweekly): The estimated time it will take to fully pay off the loan.
  • Amortization Table & Chart: These visualize how your loan balance decreases over time under each payment scenario, highlighting the accelerated principal reduction with biweekly payments.

Decision-Making Guidance:

Use the results to assess if the biweekly payment strategy aligns with your financial goals. If the interest savings and earlier payoff time are significant enough for your situation, consider implementing this strategy. Remember to verify with your lender how biweekly payments are processed to ensure they are applied directly to the principal.

Key Factors Affecting Biweekly vs. Monthly Mortgage Results

Several factors significantly influence the outcome when comparing biweekly vs monthly mortgage payment strategies. Understanding these can help you interpret the calculator's results and make informed decisions:

  1. Interest Rate (APR): This is perhaps the most crucial factor. A higher interest rate means more interest accrues over time. Consequently, the extra principal payments from a biweekly schedule will have a more substantial impact on reducing total interest paid and shortening the loan term. The higher the rate, the more attractive the biweekly strategy becomes.
  2. Loan Term: For longer loan terms (like 30 years), the potential for interest savings with biweekly payments is much greater compared to shorter terms (like 15 years). This is because interest has more time to accumulate on a longer amortization schedule.
  3. Loan Amount (Principal): A larger principal amount means more interest will be paid over the life of the loan, assuming the same interest rate and term. Therefore, the absolute dollar savings from biweekly payments will be higher on larger loan amounts.
  4. Lender Policies & Fees: Some lenders offer formal biweekly payment plans. It's essential to understand if there are any setup fees or administrative charges associated with these programs. Some plans might not apply your extra payments directly to the principal effectively, diminishing the benefits. You can often achieve the same or better results by manually making an extra principal payment once a year. Our calculator assumes direct principal application.
  5. Your Cash Flow Management: While biweekly payments result in paying more annually (13 months' worth), the payments are smaller and more frequent. You need to ensure your budget can handle slightly smaller, more frequent outflows comfortably, rather than one larger monthly payment. This is about managing cash flow effectively.
  6. Inflation and Opportunity Cost: While paying down your mortgage faster is generally good, consider the opportunity cost. Could the money used for extra principal payments generate a higher return if invested elsewhere, especially in a low-interest-rate environment? This is a complex financial decision involving risk tolerance and investment strategies.
  7. Taxes and Deductions: Mortgage interest is often tax-deductible. Paying off your mortgage faster means you'll benefit from this deduction for a shorter period. While saving interest is usually paramount, it's worth considering the long-term tax implications, though this is typically secondary to the substantial interest savings.

Frequently Asked Questions (FAQ)

What is the primary benefit of a biweekly mortgage payment?
The main benefit is saving money on interest and paying off your mortgage faster. By making the equivalent of one extra monthly payment each year, you reduce the principal balance more quickly, leading to substantial interest savings over the life of the loan.
Does a biweekly payment plan automatically reduce my loan term?
Yes, by consistently making the equivalent of 13 monthly payments per year instead of 12, you accelerate principal reduction. This typically shaves several years off a 30-year mortgage, often reducing it to around 25-26 years.
Are there any risks associated with biweekly mortgage payments?
The main risk is if your lender doesn't properly apply the extra payments directly to the principal. Some lenders might just hold the funds until the next payment is due. It's crucial to confirm their policy. There's also the minor risk of cash flow strain if you don't budget correctly for the more frequent payments.
Can I implement a biweekly payment plan myself without a lender program?
Absolutely. You can achieve the same results by manually making an extra principal payment equal to half your monthly mortgage payment once or twice a year. Alternatively, you can simply add an extra full principal payment annually. Ensure you specify that the extra amount is for principal reduction.
How much interest can I realistically save with a biweekly plan?
The savings vary significantly based on the loan amount, interest rate, and remaining term. However, for a typical 30-year mortgage, savings can range from tens of thousands to over a hundred thousand dollars. Our biweekly vs monthly mortgage calculator provides a personalized estimate.
What if my interest rate changes (e.g., on an adjustable-rate mortgage)?
If your interest rate increases, the total interest paid will be higher under both plans, but the biweekly plan will likely still save you more interest and time due to the accelerated principal payoff. If your rate decreases, the benefits of the biweekly plan may be slightly reduced, but it remains a sound strategy for faster debt reduction.
Does a biweekly payment plan affect my credit score differently?
Not directly. Paying down your mortgage faster or paying extra towards principal doesn't inherently impact your credit score differently than making regular monthly payments. However, by reducing your overall debt faster, you improve your debt-to-income ratio, which can indirectly support a healthier credit profile.
Is a biweekly payment plan suitable for all homeowners?
It's most beneficial for homeowners who want to save on interest and pay off their mortgage early, and who have stable finances to manage the payment schedule. It might be less suitable for those on a very tight budget or who prefer to keep their cash reserves readily available for other potential investments or emergencies. Consulting a financial advisor is always recommended.

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return false; } errorElement.style.display = 'none'; return true; } function calculateMortgage() { // Validate inputs var isValidLoanAmount = validateInput('loanAmount', 'loanAmountError', 0); var isValidInterestRate = validateInput('annualInterestRate', 'annualInterestRateError', 0, 100); var isValidLoanTerm = validateInput('loanTermYears', 'loanTermYearsError', 1); if (!isValidLoanAmount || !isValidInterestRate || !isValidLoanTerm) { document.getElementById('mainResult').innerText = "Invalid Input"; return; } var principal = parseFloat(document.getElementById('loanAmount').value); var annualRate = parseFloat(document.getElementById('annualInterestRate').value) / 100; var years = parseInt(document.getElementById('loanTermYears').value); var monthlyRate = annualRate / 12; var numPayments = years * 12; // Calculate monthly payment (M) var monthlyPayment = (principal * monthlyRate) / (1 – Math.pow(1 + monthlyRate, -numPayments)); var monthlyTotalInterest = (monthlyPayment * numPayments) – principal; var monthlyPayoffTime = years; // Calculate bi-weekly payment and its impact var biweeklyPaymentAmount = monthlyPayment / 2; var biweeklyPaymentsPerYear = 26; var totalPaidBiweeklyPerYear = biweeklyPaymentAmount * biweeklyPaymentsPerYear; var extraPaymentPerYear = totalPaidBiweeklyPerYear – (monthlyPayment * 12); // This is effectively one extra monthly payment var remainingBalance = principal; var biweeklyInterestPaid = 0; var biweeklyPaymentsMade = 0; var biweeklyTotalPaid = 0; var amortizationData = []; // For chart and table // Simulate bi-weekly amortization while (remainingBalance > 0) { var paymentToApply = Math.min(biweeklyPaymentAmount, remainingBalance + (remainingBalance * monthlyRate)); // Ensure not overpaying principal at the end var interestThisPeriod = remainingBalance * monthlyRate; var principalThisPeriod = paymentToApply – interestThisPeriod; // Handle potential floating point inaccuracies at the very end if (principalThisPeriod > remainingBalance) { principalThisPeriod = remainingBalance; paymentToApply = principalThisPeriod + interestThisPeriod; } if (paymentToApply > remainingBalance + interestThisPeriod) { paymentToApply = remainingBalance + interestThisPeriod; } remainingBalance -= principalThisPeriod; biweeklyInterestPaid += interestThisPeriod; biweeklyTotalPaid += paymentToApply; biweeklyPaymentsMade++; // Add data for chart/table every 6 months (approximately) if (biweeklyPaymentsMade % 26 === 0 || remainingBalance years * 12 * 2) { // Safety break console.error("Biweekly calculation exceeded safety limit."); break; } } var biweeklyPayoffYears = biweeklyPaymentsMade / 26; // Calculate total interest for monthly plan for comparison reference point (assuming exactly 30 years or n payments) var monthlyTotalInterestVal = (monthlyPayment * numPayments) – principal; // Calculate total interest for bi-weekly plan var biweeklyTotalInterestVal = biweeklyTotalInterest; // Calculate total savings var totalInterestSavings = monthlyTotalInterestVal – biweeklyTotalInterestVal; document.getElementById('mainResult').innerText = formatCurrency(totalInterestSavings); document.getElementById('monthlyTotalInterest').innerText = formatCurrency(monthlyTotalInterestVal); document.getElementById('biweeklyTotalInterest').innerText = formatCurrency(biweeklyTotalInterestVal); document.getElementById('monthlyPayoffTime').innerText = formatYears(years); document.getElementById('biweeklyPayoffTime').innerText = formatYears(biweeklyPayoffYears); // Populate Table populateTable(amortizationData, principal, monthlyPayment, years, years * 12); // Update Chart updateChart(amortizationData, principal, monthlyPayment, years); document.getElementById('results').style.display = 'block'; } function populateTable(biweeklyData, principal, monthlyPayment, monthlyYears, monthlyNumPayments) { var tableBody = document.querySelector("#amortizationTable tbody"); tableBody.innerHTML = "; // Clear previous data var currentMonthlyBalance = principal; var currentMonthlyInterestPaid = 0; var currentMonthlyPrincipalPaid = 0; 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principalThisYear += principalThisMonth; } monthlyRow.totalPaid = currentMonthlyPrincipalPaid + currentMonthlyInterestPaid; monthlyRow.totalInterest = currentMonthlyInterestPaid; monthlyRow.principalPaid = currentMonthlyPrincipalPaid; monthlyRow.balance = currentMonthlyBalance; monthlyRow.payments = monthlyPaymentCount; // Find corresponding bi-weekly data for the end of the year var biweeklyRowData = null; while(biweeklyIndex 0) { biweeklyRowData = biweeklyData[biweeklyIndex – 1]; } else if (!biweeklyRowData && biweeklyIndex === 0) { // Handle case where year 0 biweekly data might not be captured yet biweeklyRowData = { year: 0, totalPaid: 0, totalInterest: 0, balance: principal, payments: 0 }; } // Add rows to table var row = tableBody.insertRow(); var cellYear = row.insertCell(); cellYear.textContent = year === 0 ? 'Start' : year; var cellTypeMonthly = row.insertCell(); cellTypeMonthly.textContent = 'Monthly'; var cellPaidMonthly = row.insertCell(); cellPaidMonthly.textContent = formatCurrency(monthlyRow.principalPaid + monthlyRow.totalInterest); var cellInterestMonthly = row.insertCell(); cellInterestMonthly.textContent = formatCurrency(monthlyRow.totalInterest); var cellPrincipalMonthly = row.insertCell(); cellPrincipalMonthly.textContent = formatCurrency(monthlyRow.principalPaid); var cellBalanceMonthly = row.insertCell(); cellBalanceMonthly.textContent = formatCurrency(monthlyRow.balance); // Bi-weekly data (only if available and year matches or is closest) if (biweeklyRowData && biweeklyRowData.year === year) { var rowBiweekly = tableBody.insertRow(); var cellYearBiweekly = rowBiweekly.insertCell(); cellYearBiweekly.textContent = year === 0 ? 'Start' : year; var cellTypeBiweekly = rowBiweekly.insertCell(); cellTypeBiweekly.textContent = 'Bi-weekly'; var cellPaidBiweekly = rowBiweekly.insertCell(); cellPaidBiweekly.textContent = formatCurrency(biweeklyRowData.totalPaid); var cellInterestBiweekly = rowBiweekly.insertCell(); cellInterestBiweekly.textContent = formatCurrency(biweeklyRowData.totalInterest); var cellPrincipalBiweekly = rowBiweekly.insertCell(); cellPrincipalBiweekly.textContent = formatCurrency(biweeklyRowData.principalPaid); var cellBalanceBiweekly = rowBiweekly.insertCell(); cellBalanceBiweekly.textContent = formatCurrency(biweeklyRowData.balance); } } } function updateChart(biweeklyData, principal, monthlyPayment, monthlyYears) { var ctx = document.getElementById('amortizationChart').getContext('2d'); if (window.myChart) { window.myChart.destroy(); // Destroy previous chart instance } var chartLabels = []; var monthlyBalances = []; var biweeklyBalances = []; var currentMonthlyBalance = principal; var currentBiweeklyBalance = principal; var biweeklyIndex = 0; // Generate labels and data points for monthly for (var year = 0; year <= monthlyYears; year++) { chartLabels.push(year + ' Years'); monthlyBalances.push(currentMonthlyBalance); // Simulate monthly payment for the year var paymentsThisYear = 0; for(var month = 0; month < 12; month++){ if(currentMonthlyBalance currentMonthlyBalance) { principalThisMonth = currentMonthlyBalance; } currentMonthlyBalance -= principalThisMonth; paymentsThisYear++; } if (currentMonthlyBalance < 0) currentMonthlyBalance = 0; // Avoid negative balance // Find corresponding bi-weekly data var biweeklyYearData = null; while(biweeklyIndex 0) { biweeklyBalances.push(biweeklyData[biweeklyIndex – 1].balance); } else { biweeklyBalances.push(currentMonthlyBalance); // fallback if no biweekly data yet for year 0 } } } // Adjust biweekly balances if the loop finished early while (biweeklyBalances.length < monthlyBalances.length) { if (biweeklyIndex < biweeklyData.length) { biweeklyBalances.push(biweeklyData[biweeklyIndex].balance); biweeklyIndex++; } else { // Fill remaining with last known balance if biweekly finished early biweeklyBalances.push(biweeklyBalances[biweeklyBalances.length – 1] || 0); } } ctx.canvas.height = 300; // Set a fixed height for the canvas window.myChart = new Chart(ctx, { type: 'line', data: { labels: chartLabels, datasets: [{ label: 'Monthly Remaining Balance', data: monthlyBalances, borderColor: 'rgb(0, 74, 153)', // Primary color backgroundColor: 'rgba(0, 74, 153, 0.1)', fill: false, tension: 0.1 }, { label: 'Biweekly Remaining Balance', data: biweeklyBalances, borderColor: 'rgb(40, 167, 69)', // Success color backgroundColor: 'rgba(40, 167, 69, 0.1)', fill: false, tension: 0.1 }] }, options: { responsive: true, maintainAspectRatio: false, scales: { y: { beginAtZero: true, title: { display: true, text: 'Remaining Balance ($)' } }, x: { title: { display: true, text: 'Loan Term (Years)' } } }, plugins: { title: { display: true, text: 'Mortgage Balance Over Time' }, legend: { position: 'top' } } } }); } function resetForm() { document.getElementById('loanAmount').value = '300000'; document.getElementById('annualInterestRate').value = '5'; document.getElementById('loanTermYears').value = '30'; document.getElementById('loanAmountError').style.display = 'none'; document.getElementById('annualInterestRateError').style.display = 'none'; document.getElementById('loanTermYearsError').style.display = 'none'; calculateMortgage(); // Recalculate with default values } function copyResults() { var mainResult = document.getElementById('mainResult').innerText; var monthlyTotalInterest = document.getElementById('monthlyTotalInterest').innerText; var biweeklyTotalInterest = document.getElementById('biweeklyTotalInterest').innerText; var monthlyPayoffTime = document.getElementById('monthlyPayoffTime').innerText; var biweeklyPayoffTime = document.getElementById('biweeklyPayoffTime').innerText; var loanAmount = document.getElementById('loanAmount').value; var annualInterestRate = document.getElementById('annualInterestRate').value; var loanTermYears = document.getElementById('loanTermYears').value; var copyText = "Biweekly vs. Monthly Mortgage Calculator Results:\n\n"; copyText += "Key Assumptions:\n"; copyText += "- Loan Amount: $" + loanAmount + "\n"; copyText += "- Annual Interest Rate: " + annualInterestRate + "%\n"; copyText += "- Loan Term: " + loanTermYears + " Years\n\n"; copyText += "Main Result:\n"; copyText += "- Total Interest Savings (Bi-weekly vs Monthly): " + mainResult + "\n\n"; copyText += "Monthly Payment Plan:\n"; copyText += "- Total Interest Paid: " + monthlyTotalInterest + "\n"; copyText += "- Payoff Time: " + monthlyPayoffTime + "\n\n"; copyText += "Bi-weekly Payment Plan:\n"; copyText += "- Total Interest Paid: " + biweeklyTotalInterest + "\n"; copyText += "- Payoff Time: " + biweeklyPayoffTime + "\n"; // Use a temporary textarea to copy var textArea = document.createElement("textarea"); textArea.value = copyText; textArea.style.position = "fixed"; textArea.style.opacity = 0; document.body.appendChild(textArea); textArea.focus(); textArea.select(); try { var successful = document.execCommand('copy'); var msg = successful ? 'Results copied to clipboard!' : 'Failed to copy results.'; var successMessageElement = document.getElementById('results-copy-message'); successMessageElement.textContent = msg; successMessageElement.style.display = 'block'; setTimeout(function() { successMessageElement.style.display = 'none'; }, 3000); } catch (err) { var successMessageElement = document.getElementById('results-copy-message'); successMessageElement.textContent = 'Failed to copy results.'; successMessageElement.style.display = 'block'; setTimeout(function() { successMessageElement.style.display = 'none'; }, 3000); } document.body.removeChild(textArea); } // FAQ functionality document.addEventListener('DOMContentLoaded', function() { var faqItems = document.querySelectorAll('.faq-item .question'); faqItems.forEach(function(item) { item.addEventListener('click', function() { var parent = this.parentElement; parent.classList.toggle('open'); var answer = parent.querySelector('.answer'); if (parent.classList.contains('open')) { answer.style.display = 'block'; } else { answer.style.display = 'none'; } }); }); // Initial calculation on load calculateMortgage(); }); // Load Chart.js library dynamically if not already loaded if (typeof Chart === 'undefined') { var script = document.createElement('script'); script.src = 'https://cdn.jsdelivr.net/npm/chart.js'; script.onload = function() { // Re-calculate once chart library is loaded, if initial calculation already happened // This ensures chart is rendered correctly on first load if library is slow if (document.getElementById('amortizationChart').getContext('2d')) { // calculateMortgage(); // might be called twice, but ensures chart is ready } }; document.head.appendChild(script); }

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