Estimate your loan payments, total interest, and more with our comprehensive tool.
Loan Details
Enter the total amount you wish to borrow.
Enter the yearly interest rate (e.g., 5 for 5%).
Enter the total duration of the loan in years.
Standard Amortizing Loan
Interest-Only Loan
Balloon Loan
Select the type of loan for accurate calculations.
Your Loan Summary
$0.00
Monthly Payment: $0.00
Total Interest Paid: $0.00
Total Repayment: $0.00
Principal Paid: $0.00
Monthly Payment (Standard) = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
Where P = Principal Loan Amount, i = Monthly Interest Rate, n = Total Number of Payments.
Interest-Only & Balloon loan calculations differ.
Amortization Schedule
Loan Balance and Principal vs. Time
Loan Amortization Details
Payment #
Date
Starting Balance
Payment
Interest Paid
Principal Paid
Ending Balance
Enter loan details and click Calculate.
What is an All-in-One Loan Calculator?
An All-in-One Loan Calculator is a versatile financial tool designed to help individuals and businesses estimate the costs and repayment structures associated with various types of loans. Unlike single-purpose calculators that focus on one loan type (like a mortgage or a car loan), this comprehensive calculator aims to provide a unified platform for comparing and understanding different borrowing scenarios. It simplifies complex financial calculations, allowing users to input key loan parameters such as the principal amount, annual interest rate, loan term, and loan type, and then instantly receive detailed breakdowns of their potential financial obligations.
This tool is invaluable for anyone considering taking out a loan, whether it's for a home purchase, a vehicle, education, business expansion, or personal expenses. It empowers users by providing clarity on monthly payments, the total interest they will pay over the life of the loan, and how the principal is gradually paid down. By offering insights into different loan types like standard amortizing loans, interest-only loans, and balloon loans, the calculator facilitates informed decision-making, helping users choose the loan product that best fits their financial situation and long-term goals.
Individuals seeking to finance a car or other large purchases.
Students planning for educational expenses.
Entrepreneurs and business owners looking for funding.
Anyone comparing different loan offers or considering refinancing.
Common Misconceptions
Misconception: All loans have the same repayment structure. Reality: Loan types like interest-only and balloon loans have significantly different repayment profiles than standard amortizing loans.
Misconception: The advertised interest rate is the only cost. Reality: Fees, points, and other charges can increase the overall cost of borrowing.
Misconception: A lower monthly payment is always better. Reality: A lower monthly payment might mean paying more interest over time or a larger final payment (balloon loan).
All-in-One Loan Calculator Formula and Mathematical Explanation
The core of any loan calculator lies in its ability to accurately compute payments and interest. Our All-in-One Loan Calculator utilizes standard financial formulas, adapting them based on the selected loan type.
Standard Amortizing Loan Formula
For a standard amortizing loan, the monthly payment (M) is calculated using the following formula:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
Where:
P = Principal Loan Amount (the total amount borrowed)
n = Total Number of Payments (Loan Term in Years * 12)
This formula ensures that each payment covers both the interest accrued for that period and a portion of the principal, gradually reducing the loan balance to zero by the end of the term.
Interest-Only Loan Calculation
For an interest-only loan, the calculation is simpler during the interest-only period:
Monthly Interest Payment = P * i
During this phase, the borrower only pays the interest accrued, and the principal balance remains unchanged. After the interest-only period, the loan typically converts to a standard amortizing loan, or a balloon payment is due.
Balloon Loan Calculation
Balloon loans often have a lower initial payment, calculated similarly to an interest-only loan or a partially amortizing loan over a shorter term than the full repayment period. However, a large "balloon" payment of the remaining principal is due at the end of the loan term.
Where 'k' is the number of payments during the initial term before the balloon payment is due. The final balloon payment equals the remaining principal balance.
Variables Table
Loan Calculation Variables
Variable
Meaning
Unit
Typical Range
P (Principal)
The total amount of money borrowed.
Currency ($)
$1,000 – $1,000,000+
Annual Interest Rate
The yearly rate charged on the loan principal.
Percentage (%)
1% – 30%+
i (Monthly Rate)
The interest rate applied per month.
Decimal (e.g., 0.05/12)
Calculated
Loan Term (Years)
The total duration of the loan agreement.
Years
1 – 30+ Years
n (Total Payments)
The total number of monthly payments over the loan term.
Count
12 – 360+
M (Monthly Payment)
The fixed amount paid each month.
Currency ($)
Calculated
Total Interest Paid
The sum of all interest payments over the loan's life.
Currency ($)
Calculated
Total Repayment
The sum of all payments (principal + interest).
Currency ($)
Calculated
Practical Examples (Real-World Use Cases)
Example 1: Standard Mortgage Calculation
Sarah is looking to buy a house and needs a mortgage. She finds a property requiring a $300,000 loan. The bank offers her a 30-year fixed-rate mortgage at 6.5% annual interest. She wants to know her estimated monthly payment and the total interest she'll pay.
Inputs:
Loan Amount: $300,000
Annual Interest Rate: 6.5%
Loan Term: 30 Years
Loan Type: Standard Amortizing Loan
Using the All-in-One Loan Calculator:
Estimated Monthly Payment: $1,896.20
Total Interest Paid: $382,631.94
Total Repayment: $682,631.94
Financial Interpretation: Sarah's monthly mortgage payment (principal and interest) would be approximately $1,896.20. Over 30 years, she would end up paying $382,631.94 in interest alone, which is more than the original loan amount. This highlights the significant long-term cost of borrowing for a home.
Example 2: Business Loan Comparison (Interest-Only vs. Standard)
A small business owner needs $50,000 for equipment. They are comparing two loan options over 5 years (60 months):
Option A: Standard Amortizing Loan at 8% annual interest.
Option B: Interest-Only Loan for the first 2 years (24 months) at 7% annual interest, then converting to a standard amortizing loan for the remaining 3 years (36 months) at 8% annual interest.
Inputs & Results (Option A – Standard):
Loan Amount: $50,000
Annual Interest Rate: 8%
Loan Term: 5 Years
Loan Type: Standard Amortizing Loan
Monthly Payment: $1,053.57
Total Interest Paid: $13,214.08
Total Repayment: $63,214.08
Inputs & Results (Option B – Interest-Only then Standard):
Monthly Payments (Months 25-60): $1,515.30 (calculated on $50,000 over 36 months at 8%)
Total Interest Paid: ($291.67 * 24) + ($13,214.08 – interest paid on $50k over 36mo at 8%) = $7,000 + $8,000 approx = $15,000 (approx)
Total Repayment: $50,000 + Total Interest Paid (approx $15,000) = $65,000 (approx)
Financial Interpretation: Option B offers lower initial payments ($291.67 vs $1,053.57) for the first two years, which might help cash flow. However, the total interest paid is higher ($15,000 vs $13,214.08), and the later payments are significantly higher ($1,515.30 vs $1,053.57). This comparison helps the business owner weigh immediate affordability against long-term cost.
How to Use This All-in-One Loan Calculator
Our All-in-One Loan Calculator is designed for ease of use, providing quick and accurate financial insights. Follow these simple steps to get started:
Step-by-Step Instructions
Enter Loan Amount: Input the total sum of money you need to borrow in the "Loan Amount ($)" field.
Input Annual Interest Rate: Enter the yearly interest rate offered for the loan in the "Annual Interest Rate (%)" field. Use decimals for precision if needed (e.g., 6.5 for 6.5%).
Specify Loan Term: Enter the total duration of the loan in years in the "Loan Term (Years)" field. For example, a 15-year mortgage would be entered as 15.
Select Loan Type: Choose the appropriate loan structure from the dropdown menu:
Standard Amortizing Loan: Payments include both principal and interest, gradually reducing the balance to zero.
Interest-Only Loan: Payments cover only the interest for a specified period; the principal remains unchanged.
Balloon Loan: Features lower initial payments, with a large final "balloon" payment of the remaining principal due at the end of the term.
Click 'Calculate': Once all details are entered, click the "Calculate" button.
How to Read Results
After clicking "Calculate," you will see the following key outputs:
Primary Highlighted Result (Monthly Payment): This is your estimated fixed monthly payment (for standard loans) or the initial payment amount.
Intermediate Values:
Total Interest Paid: The total amount of interest you will pay over the entire life of the loan.
Total Repayment: The sum of the loan principal and all interest paid.
Principal Paid: The portion of your payments that reduces the actual loan balance (relevant for standard loans).
Amortization Schedule Table: A detailed breakdown of each payment, showing the date, starting balance, payment amount, interest portion, principal portion, and ending balance for every payment period.
Dynamic Chart: A visual representation of your loan's progress, typically showing the remaining balance over time and how much of each payment goes towards principal versus interest.
Decision-Making Guidance
Use the results to:
Compare Loan Offers: Input details from different loan quotes to see which offers the lowest overall cost or most manageable payments.
Assess Affordability: Determine if the calculated monthly payment fits comfortably within your budget.
Understand Long-Term Costs: Evaluate the total interest paid to grasp the true cost of borrowing.
Plan for Future Payments: For interest-only or balloon loans, understand the payment structure and the significant final payment.
Utilize the 'Copy Results' Button: Easily transfer your calculated summary to documents or emails for record-keeping or sharing.
Remember to also consider other loan costs like origination fees, closing costs, and insurance, which are not included in this basic calculator but are crucial for a complete financial picture.
Key Factors That Affect All-in-One Loan Calculator Results
Several critical factors influence the outcomes generated by any loan calculator, including our All-in-One tool. Understanding these elements is key to interpreting the results accurately and making sound financial decisions.
Interest Rate (APR)
This is arguably the most significant factor. A higher annual interest rate directly increases the monthly payment and the total interest paid over the loan's life. Even small differences in rates can lead to substantial cost variations over long terms, especially for large loans like mortgages. The Annual Percentage Rate (APR) is often a better comparison point than just the nominal interest rate, as it includes certain fees.
Loan Principal Amount
The larger the amount borrowed, the higher the monthly payments and the total interest paid will be, assuming all other factors remain constant. This is the base upon which interest is calculated, so a higher principal means more interest accrues over time.
Loan Term (Duration)
A longer loan term generally results in lower monthly payments but significantly increases the total interest paid. Conversely, a shorter term means higher monthly payments but less interest paid overall. Choosing the right term involves balancing immediate affordability with long-term cost savings.
Loan Type Structure
As demonstrated, the type of loan (standard, interest-only, balloon) drastically changes the payment schedule and total cost. Interest-only loans offer lower initial payments but don't reduce the principal, leading to higher total interest or a large final payment. Balloon loans defer principal repayment, creating a large lump sum due later.
Fees and Other Charges
While this calculator focuses on principal and interest, real-world loans often come with various fees (origination fees, appraisal fees, closing costs, late fees, prepayment penalties). These fees add to the overall cost of borrowing and should be factored into affordability assessments. Some calculators might incorporate an APR that includes certain fees.
Inflation and Economic Conditions
Inflation erodes the purchasing power of money over time. While not directly calculated, it affects the *real* cost of future payments. A loan taken out during high inflation might feel cheaper to repay later in nominal terms, but the lender is also compensated for this expected erosion of value through the interest rate. Economic conditions also influence interest rate trends.
Prepayment Options and Penalties
The ability to make extra payments towards the principal can significantly reduce the total interest paid and shorten the loan term. Conversely, if a loan has prepayment penalties, paying extra might incur additional costs, affecting the overall financial benefit.
Tax Implications
In some cases, the interest paid on certain loans (like mortgages) may be tax-deductible. This can reduce the effective cost of borrowing. Tax laws vary by jurisdiction and individual circumstances, so consulting a tax professional is advisable.
Frequently Asked Questions (FAQ)
Q: What is the difference between APR and interest rate?
A: The interest rate is the cost of borrowing money expressed as a percentage of the principal. The APR (Annual Percentage Rate) includes the interest rate plus certain other fees and costs associated with the loan, providing a more comprehensive measure of the total cost of borrowing over a year.
Q: Can I use this calculator for loans other than mortgages?
A: Yes! This All-in-One Loan Calculator is designed to handle various loan types, including auto loans, personal loans, student loans, and business loans, provided you input the correct principal, rate, and term.
Q: How accurate are the results?
A: The calculator uses standard financial formulas for accuracy. However, results are estimates. Actual loan payments may vary slightly due to lender-specific calculation methods, rounding differences, or additional fees not included in the calculator.
Q: What does "amortization" mean?
A: Amortization is the process of paying off a debt over time through regular, scheduled payments. Each payment consists of both interest and principal. In an amortizing loan, the portion of the payment applied to interest decreases over time, while the portion applied to principal increases.
Q: Should I choose a shorter or longer loan term?
A: A shorter term means higher monthly payments but less total interest paid. A longer term means lower monthly payments but more total interest paid. The best choice depends on your budget and financial goals. Use the calculator to compare scenarios.
Q: What happens if I miss a payment?
A: Missing a payment typically results in late fees and can negatively impact your credit score. For amortizing loans, it may also extend the loan term or increase future payments depending on the lender's policies. Check your loan agreement for details.
Q: Can I pay off my loan early?
A: Many loans allow early payoff, often without penalty. Making extra payments towards the principal can save you significant money on interest over time. Some loans, however, may charge a prepayment penalty.
Q: How do interest-only and balloon loans differ from standard loans?
A: Standard loans gradually pay down both principal and interest. Interest-only loans only pay interest for a set period, leaving the principal untouched. Balloon loans have lower initial payments but require a large lump-sum payment of the remaining principal at the end of the term.
var chartInstance = null; // Global variable to hold chart instance
function formatCurrency(amount) {
return amount.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
function formatNumber(num) {
return num.toFixed(2);
}
function calculateLoan() {
// Clear previous errors
clearErrors();
// Get input values
var principal = parseFloat(document.getElementById("loanAmount").value);
var annualRate = parseFloat(document.getElementById("annualInterestRate").value);
var years = parseInt(document.getElementById("loanTermYears").value);
var loanType = document.getElementById("loanType").value;
// Validate inputs
if (isNaN(principal) || principal < 0) {
showError("loanAmountError", "Please enter a valid loan amount.");
return;
}
if (isNaN(annualRate) || annualRate 100) {
showError("annualInterestRateError", "Please enter a valid annual interest rate between 0% and 100%.");
return;
}
if (isNaN(years) || years 0) {
monthlyPayment = principal * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else {
monthlyPayment = principal / numberOfPayments; // Handle 0% interest
}
totalRepayment = monthlyPayment * numberOfPayments;
totalInterest = totalRepayment – principal;
principalPaid = principal; // In standard loan, entire principal is paid off
// Generate amortization schedule
var balance = principal;
var currentDate = new Date();
for (var i = 0; i < numberOfPayments; i++) {
var interestPayment = balance * monthlyRate;
var principalPayment = monthlyPayment – interestPayment;
// Adjust last payment to ensure balance is exactly 0
if (i === numberOfPayments – 1) {
principalPayment = balance;
monthlyPayment = interestPayment + principalPayment;
totalRepayment = monthlyPayment * (i + 1) + (principal * (i+1) – principal); // Recalculate total repayment based on actual payments
totalInterest = totalRepayment – principal;
}
balance -= principalPayment;
if (balance < 0) balance = 0; // Ensure balance doesn't go negative due to rounding
amortizationData.push({
paymentNum: i + 1,
date: new Date(currentDate.getFullYear(), currentDate.getMonth() + i, 1).toLocaleDateString('en-US', { year: 'numeric', month: 'short', day: 'numeric' }),
startBalance: parseFloat(principal) – amortizationData.reduce(function(sum, item) { return sum + item.principalPaid; }, 0),
payment: monthlyPayment,
interestPaid: interestPayment,
principalPaid: principalPayment,
endBalance: balance
});
}
} else if (loanType === "interestOnly") {
monthlyPayment = principal * monthlyRate;
totalInterest = monthlyPayment * numberOfPayments;
totalRepayment = principal + totalInterest;
principalPaid = 0; // No principal paid during interest-only period
// Amortization for interest-only shows constant principal
var balance = principal;
var currentDate = new Date();
for (var i = 0; i < numberOfPayments; i++) {
amortizationData.push({
paymentNum: i + 1,
date: new Date(currentDate.getFullYear(), currentDate.getMonth() + i, 1).toLocaleDateString('en-US', { year: 'numeric', month: 'short', day: 'numeric' }),
startBalance: principal,
payment: monthlyPayment,
interestPaid: monthlyPayment,
principalPaid: 0,
endBalance: principal
});
}
// Add a note about the balloon payment
document.getElementById("results").innerHTML += '
Note: A large balloon payment equal to the principal ($' + formatCurrency(principal) + ') is due at the end of the term.
';
} else if (loanType === "balloon") {
// Simplified balloon calculation: Assume a standard payment calculation for a shorter term, then a balloon payment.
// For a more complex balloon, you'd need a specific balloon term and rate.
// Here, we'll calculate a standard payment for the full term, but note the balloon.
// A true balloon loan might have a different calculation for the initial payment based on a shorter amortization schedule.
// For simplicity, let's assume the user wants to know the payment if it were standard, but is aware of a balloon.
// A more accurate approach would require defining the balloon term separately.
// Let's calculate a standard payment and then state the balloon payment is the remaining principal.
if (monthlyRate > 0) {
monthlyPayment = principal * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else {
monthlyPayment = principal / numberOfPayments;
}
totalRepayment = monthlyPayment * numberOfPayments; // This is an estimate if it were standard
totalInterest = totalRepayment – principal; // Estimate
principalPaid = principal; // This is the total principal to be paid
// For a balloon loan, the final payment is the remaining balance.
// Let's simulate a scenario where the payment is calculated for a shorter term, e.g., 5 years, but the loan is 30 years.
// This requires more inputs (e.g., balloon term).
// For this generic calculator, we'll calculate a standard payment and add a note.
// A common balloon structure is interest-only for a period, then a large principal payment.
// Let's assume interest-only for simplicity here, with the full principal due at the end.
monthlyPayment = principal * monthlyRate; // Interest-only payment
totalInterest = monthlyPayment * numberOfPayments;
totalRepayment = principal + totalInterest; // Principal + all interest
principalPaid = 0; // No principal paid until balloon
// Amortization for balloon (interest-only) shows constant principal
var balance = principal;
var currentDate = new Date();
for (var i = 0; i < numberOfPayments; i++) {
amortizationData.push({
paymentNum: i + 1,
date: new Date(currentDate.getFullYear(), currentDate.getMonth() + i, 1).toLocaleDateString('en-US', { year: 'numeric', month: 'short', day: 'numeric' }),
startBalance: principal,
payment: monthlyPayment,
interestPaid: monthlyPayment,
principalPaid: 0,
endBalance: principal
});
}
// Add a note about the balloon payment
document.getElementById("results").innerHTML += '
Note: A large balloon payment equal to the principal ($' + formatCurrency(principal) + ') is due at the end of the term.
';
}
// Display results
document.getElementById("primaryResult").textContent = "$" + formatCurrency(monthlyPayment);
document.getElementById("monthlyPayment").textContent = "Monthly Payment: $" + formatCurrency(monthlyPayment);
document.getElementById("totalInterestPaid").textContent = "Total Interest Paid: $" + formatCurrency(totalInterest);
document.getElementById("totalRepayment").textContent = "Total Repayment: $" + formatCurrency(totalRepayment);
document.getElementById("principalPaid").textContent = "Principal Paid: $" + formatCurrency(principalPaid);
// Update amortization table
var tableBody = document.getElementById("amortizationTableBody");
tableBody.innerHTML = ""; // Clear previous rows
if (amortizationData.length > 0) {
amortizationData.forEach(function(row) {
var tr = tableBody.insertRow();
tr.insertCell().textContent = row.paymentNum;
tr.insertCell().textContent = row.date;
tr.insertCell().textContent = "$" + formatCurrency(row.startBalance);
tr.insertCell().textContent = "$" + formatCurrency(row.payment);
tr.insertCell().textContent = "$" + formatCurrency(row.interestPaid);
tr.insertCell().textContent = "$" + formatCurrency(row.principalPaid);
tr.insertCell().textContent = "$" + formatCurrency(row.endBalance);
});
} else {
var tr = tableBody.insertRow();
tr.insertCell().colSpan = 7;
tr.insertCell().textContent = "No amortization data available for this loan type or inputs.";
}
// Update chart
updateChart(amortizationData, principal);
}
function showError(elementId, message) {
var errorElement = document.getElementById(elementId);
errorElement.textContent = message;
errorElement.style.display = "block";
document.getElementById(elementId.replace("Error", "")).classList.add("error");
}
function clearErrors() {
var errorElements = document.querySelectorAll(".error-message");
errorElements.forEach(function(el) {
el.textContent = "";
el.style.display = "none";
});
var inputFields = document.querySelectorAll(".input-group input, .input-group select");
inputFields.forEach(function(input) {
input.classList.remove("error");
});
// Clear specific result messages if any
var resultMessages = document.querySelectorAll('#results .formula-explanation');
resultMessages.forEach(function(msg) {
msg.remove();
});
}
function resetCalculator() {
document.getElementById("loanAmount").value = "200000";
document.getElementById("annualInterestRate").value = "5";
document.getElementById("loanTermYears").value = "30";
document.getElementById("loanType").value = "standard";
clearErrors();
calculateLoan(); // Recalculate with default values
}
function copyResults() {
var monthlyPayment = document.getElementById("monthlyPayment").textContent;
var totalInterest = document.getElementById("totalInterestPaid").textContent;
var totalRepayment = document.getElementById("totalRepayment").textContent;
var principalPaid = document.getElementById("principalPaid").textContent;
var loanAmount = document.getElementById("loanAmount").value;
var annualInterestRate = document.getElementById("annualInterestRate").value;
var loanTermYears = document.getElementById("loanTermYears").value;
var loanType = document.getElementById("loanType").options[document.getElementById("loanType").selectedIndex].text;
var resultText = "Loan Calculation Summary:\n\n";
resultText += "Loan Amount: $" + formatCurrency(parseFloat(loanAmount)) + "\n";
resultText += "Annual Interest Rate: " + annualInterestRate + "%\n";
resultText += "Loan Term: " + loanTermYears + " years\n";
resultText += "Loan Type: " + loanType + "\n\n";
resultText += monthlyPayment + "\n";
resultText += totalInterest + "\n";
resultText += totalRepayment + "\n";
resultText += principalPaid + "\n";
// Add notes for interest-only/balloon if present
var notes = document.querySelectorAll('#results .formula-explanation');
notes.forEach(function(note) {
resultText += note.textContent + "\n";
});
// Use a temporary textarea to copy to clipboard
var textArea = document.createElement("textarea");
textArea.value = resultText;
textArea.style.position = "fixed"; // Avoid scrolling to bottom of page in MS Edge.
textArea.style.top = 0;
textArea.style.left = 0;
textArea.style.width = '2em';
textArea.style.height = '2em';
textArea.style.padding = '0';
textArea.style.border = 'none';
textArea.style.outline = 'none';
textArea.style.boxShadow = 'none';
document.body.appendChild(textArea);
textArea.focus();
textArea.select();
try {
var successful = document.execCommand('copy');
var msg = successful ? 'Results copied!' : 'Copying text command was unsuccessful';
console.log(msg);
// Optionally show a temporary message to the user
var copyFeedback = document.createElement('div');
copyFeedback.textContent = msg;
copyFeedback.style.position = 'fixed';
copyFeedback.style.bottom = '10px';
copyFeedback.style.left = '50%';
copyFeedback.style.transform = 'translateX(-50%)';
copyFeedback.style.backgroundColor = 'var(–primary-color)';
copyFeedback.style.color = 'white';
copyFeedback.style.padding = '10px 20px';
copyFeedback.style.borderRadius = '5px';
copyFeedback.style.zIndex = '1000';
document.body.appendChild(copyFeedback);
setTimeout(function() {
copyFeedback.remove();
}, 2000);
} catch (err) {
console.log('Unable to copy text.', err);
// Fallback for browsers that don't support execCommand
alert("Could not copy text automatically. Please manually select and copy the results.");
} finally {
document.body.removeChild(textArea);
}
}
function updateChart(amortizationData, principal) {
var ctx = document.getElementById('amortizationChart').getContext('2d');
// Destroy previous chart instance if it exists
if (chartInstance) {
chartInstance.destroy();
}
var labels = amortizationData.map(function(item, index) {
// Show fewer labels for long terms to avoid clutter
if (amortizationData.length > 60 && index % 6 !== 0) return "; // Label every 6 months
if (amortizationData.length <= 60 && index % 2 !== 0) return ''; // Label every other month for shorter terms
return item.date;
}).filter(Boolean); // Remove empty strings
var principalPaidSeries = amortizationData.map(function(item) { return item.principalPaid; });
var interestPaidSeries = amortizationData.map(function(item) { return item.interestPaid; });
var cumulativePrincipal = [];
var cumulativeInterest = [];
var currentPrincipalSum = 0;
var currentInterestSum = 0;
amortizationData.forEach(function(item, index) {
currentPrincipalSum += item.principalPaid;
currentInterestSum += item.interestPaid;
cumulativePrincipal.push(currentPrincipalSum);
cumulativeInterest.push(currentInterestSum);
});
// Adjust labels array length to match data series length if needed
var dataPointsCount = amortizationData.length;
if (labels.length item !== null),
backgroundColor: 'rgba(0, 74, 153, 0.6)', // Primary color
borderColor: 'rgba(0, 74, 153, 1)',
borderWidth: 1,
type: 'line', // Display as line
fill: false,
tension: 0.1
}, {
label: 'Cumulative Interest Paid',
data: amortizationData.map(function(item, index) {
// Sample data points to match labels
if (labels.includes(item.date)) return cumulativeInterest[index];
return null;
}).filter(item => item !== null),
backgroundColor: 'rgba(40, 167, 69, 0.6)', // Success color
borderColor: 'rgba(40, 167, 69, 1)',
borderWidth: 1,
type: 'line', // Display as line
fill: false,
tension: 0.1
}]
},
options: {
responsive: true,
maintainAspectRatio: false,
scales: {
y: {
beginAtZero: true,
title: {
display: true,
text: 'Amount ($)'
},
ticks: {
callback: function(value) {
if (value % 10000 === 0) { // Show ticks every $10,000
return '$' + value.toLocaleString();
}
return null; // Don't show other ticks
}
}
},
x: {
title: {
display: true,
text: 'Time'
}
}
},
plugins: {
tooltip: {
callbacks: {
label: function(context) {
var label = context.dataset.label || ";
if (label) {
label += ': ';
}
if (context.parsed.y !== null) {
label += new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' }).format(context.parsed.y);
}
return label;
}
}
},
legend: {
position: 'top',
}
}
}
});
}
// Initial calculation on page load
document.addEventListener('DOMContentLoaded', function() {
calculateLoan();
});