Determine the worth of your future income streams.
Annuity Value Calculator
Future Value
Present Value
Choose whether to calculate the future value or present value of the annuity.
The amount paid or received each period (e.g., monthly, yearly).
The annual rate of return, expressed as a percentage (e.g., 5 for 5%).
The total number of payment periods (e.g., 120 for 10 years of monthly payments).
Annually
Semi-Annually
Quarterly
Monthly
Semi-Monthly
Bi-Weekly
Weekly
How often payments are made within a year.
Ordinary Annuity (Payments at end of period)
Annuity Due (Payments at beginning of period)
Select if payments occur at the beginning or end of each period.
Calculation Results
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Formula Used:Select calculation type to see formula.
Annuity Breakdown (Yearly)
Year
Beginning Balance
Payment Made
Interest Earned
Ending Balance
What is a Value of Annuity Calculation?
Understanding the value of an annuity is fundamental for making sound financial decisions, whether you're planning for retirement, evaluating investment opportunities, or analyzing financial contracts. An annuity is essentially a series of equal payments made at regular intervals. The "value" can refer to either its future value (what it will be worth at a specific point in the future) or its present value (what it's worth today). This value of annuity calculator helps demystify these concepts by providing clear, actionable results based on your inputs.
Who should use this calculator?
Individuals planning for long-term savings goals like retirement.
Investors evaluating the worth of financial products that offer regular payouts.
Anyone needing to understand the time value of money in the context of periodic payments.
Those comparing different annuity products or investment strategies.
Common Misconceptions about the value of an annuity:
"Annuities are only for the elderly." While often associated with retirement, annuities can be used for various savings goals and investment strategies at any age.
"All annuities offer guaranteed returns." The nature of guarantees depends heavily on the specific type of annuity and the issuing company. Many variable annuities carry investment risk.
"The stated interest rate is all that matters." Fees, charges, surrender penalties, and tax implications significantly impact the true value of an annuity over time.
"Calculating annuity value is too complex." With tools like this value of annuity calculator, the process becomes straightforward and accessible.
Value of Annuity Formula and Mathematical Explanation
The calculation of an annuity's value hinges on the principle of the time value of money. This means that a dollar today is worth more than a dollar in the future due to its potential earning capacity. The core formulas differentiate between whether you want to know the future worth of a stream of payments or the current worth of those future payments.
Future Value of an Ordinary Annuity
This calculates the total accumulated amount of an annuity at a future date, assuming payments are made at the *end* of each period.
Formula: FV = P * [((1 + i)^n – 1) / i]
Future Value of an Annuity Due
This calculates the total accumulated amount for an annuity where payments are made at the *beginning* of each period.
Formula: FV = P * [((1 + i)^n – 1) / i] * (1 + i)
Present Value of an Ordinary Annuity
This calculates the current worth of a series of future payments, assuming payments are made at the *end* of each period.
Formula: PV = P * [(1 – (1 + i)^-n) / i]
Present Value of an Annuity Due
This calculates the current worth of a series of future payments, assuming payments are made at the *beginning* of each period.
Periodic Interest Rate (Annual Rate / Payments Per Year)
Decimal (e.g., 0.05 for 5%)
Typically 0.001 to 0.20 (0.1% to 20%)
n
Total Number of Periods (Number of Years * Payments Per Year)
Count
≥ 1
Note: The 'i' and 'n' variables are crucial. The periodic interest rate 'i' is derived from the annual rate and the frequency of payments. The total number of periods 'n' also accounts for the payment frequency.
Practical Examples (Real-World Use Cases)
Example 1: Saving for Retirement (Future Value)
Sarah wants to estimate how much she'll have saved for retirement by the time she turns 65. She plans to invest $500 at the end of each month for the next 25 years. She anticipates an average annual return of 7% on her investments.
Calculation Type: Future Value
Periodic Payment (P): $500
Annual Interest Rate: 7%
Number of Years: 25
Payments Per Year: 12 (Monthly)
Annuity Type: Ordinary Annuity
Using the value of annuity calculator:
Inputs:
Periodic Payment: 500
Annual Interest Rate: 7%
Number of Periods: 300 (25 years * 12 months/year)
Payment Frequency: 12
Annuity Type: Ordinary
Outputs:
Future Value: Approximately $377,570.84
Total Payments Made: $150,000 ($500 * 300)
Total Interest Earned: Approximately $227,570.84
Financial Interpretation: Sarah's consistent monthly savings, compounded over 25 years at a 7% annual rate, could grow to over $377,000. This demonstrates the power of compounding and regular investment, highlighting the significant role interest earned plays in the final value of an annuity.
Example 2: Valuing a Lottery Payout (Present Value)
John has won a lottery and is offered a choice: receive $1,000,000 spread out as $50,000 at the beginning of each year for 20 years, or take a lump sum today. He wants to know the current worth of the payout stream to compare it with potential lump-sum offers. He uses a discount rate of 6% annually, reflecting his investment opportunities.
Calculation Type: Present Value
Periodic Payment (P): $50,000
Annual Discount Rate: 6%
Number of Years: 20
Payments Per Year: 1 (Annually)
Annuity Type: Annuity Due (payments at beginning of year)
Using the value of annuity calculator:
Inputs:
Periodic Payment: 50000
Annual Interest Rate: 6%
Number of Periods: 20 (20 years * 1 payment/year)
Payment Frequency: 1
Annuity Type: Annuity Due
Outputs:
Present Value: Approximately $689,940.38
Total Payments Made: $1,000,000 ($50,000 * 20)
Discount Rate Used (Periodic): 6%
Financial Interpretation: The $1,000,000 promised over 20 years is only worth about $689,940 today. This is because the lottery provider gets to hold onto the money and earn interest on it for longer. John should only accept a lump sum offer significantly higher than $689,940.38 to make it financially equivalent, considering the time value of money and his required rate of return. This calculation is key to understanding the true value of an annuity stream.
How to Use This Value of Annuity Calculator
Our value of annuity calculator is designed for simplicity and accuracy. Follow these steps:
Select Calculation Type: Choose whether you want to calculate the 'Future Value' (what your payments will grow to) or 'Present Value' (what your future payments are worth today).
Enter Payment Amount: Input the fixed amount of money you expect to pay or receive in each period.
Input Interest Rate: Provide the relevant annual interest rate (or discount rate for present value) as a percentage (e.g., enter '5' for 5%).
Specify Number of Periods: Enter the total number of payments you will make or receive. If your payments are monthly for 10 years, this would be 120.
Set Payment Frequency: Select how often payments are made per year (e.g., monthly, quarterly, annually). This affects the periodic interest rate and total periods.
Choose Annuity Type: Select 'Ordinary Annuity' if payments are at the end of each period, or 'Annuity Due' if payments are at the beginning.
Calculate: Click the 'Calculate' button.
Interpreting the Results:
Primary Result: This is the main calculated value – either the Future Value or Present Value of the annuity.
Intermediate Values: These provide key breakdowns like the total principal paid and the total interest earned (for future value) or total payments and discount rate (for present value).
Annuity Breakdown Table: Shows a year-by-year projection of the annuity's growth (for FV) or how the present value is composed, helping visualize the compounding effect.
Chart: Visually represents the growth or present value breakdown over time.
Decision-Making Guidance: Use the calculated Future Value to assess if your savings plan is on track for goals like retirement. Use the Present Value to compare lump-sum offers against payment streams or to determine the fair price for an annuity contract. Always consider factors beyond the raw numbers, such as inflation, taxes, and the financial strength of the issuer, when making final decisions about any value of annuity product.
Key Factors That Affect Value of Annuity Results
Several critical factors influence the calculated value of an annuity. Understanding these can help you adjust your expectations and financial strategies.
Periodic Payment Amount (P): This is the most direct driver. Larger periodic payments lead to a higher future value and a higher present value, assuming all other factors remain constant. Consistency in making these payments is key.
Interest Rate (i): The rate of return (or discount rate) is a powerful multiplier. A higher interest rate significantly increases the future value due to compounding and decreases the present value as future cash flows are discounted more heavily. Even small differences in the annual rate can have a massive impact over long periods.
Number of Periods (n): The longer the annuity runs, the greater the potential for compounding (for FV) or the more cash flows are discounted (for PV). A longer term generally leads to a substantially larger future value, while its present value might be less sensitive depending on the discount rate.
Payment Frequency: More frequent payments (e.g., monthly vs. annually) lead to slightly higher future values because interest is calculated and compounded more often within the year. For present value, the impact is also present due to more frequent discounting.
Annuity Type (Ordinary vs. Due): Payments made at the beginning of a period (Annuity Due) always result in a higher future value and a higher present value compared to payments made at the end (Ordinary Annuity), because each payment has one extra period to earn interest or is discounted one period less.
Inflation: While not directly in the standard formulas, inflation erodes the purchasing power of future money. A high future value might not have the same buying power as expected if inflation is significant. When calculating present value, the chosen discount rate should ideally reflect inflation expectations.
Fees and Charges: Many financial products structured as annuities come with various fees (management fees, administrative costs, surrender charges). These reduce the net return and therefore lower both the future and present value. Always factor in the net rate of return after fees.
Taxes: Income tax on interest earned or capital gains tax can significantly reduce the net amount received. Tax-deferred growth in some annuities can be advantageous, but withdrawals are often taxed. The ultimate value of an annuity after taxes is what truly matters.
Frequently Asked Questions (FAQ)
What is the difference between an ordinary annuity and an annuity due?
An ordinary annuity has payments made at the *end* of each period (e.g., end of the month), while an annuity due has payments made at the *beginning* of each period. Annuity due calculations result in slightly higher future and present values because payments earn interest for an additional period.
How does the interest rate affect the value of an annuity?
A higher interest rate increases the future value of an annuity because your money grows faster through compounding. Conversely, a higher discount rate (used for present value calculations) decreases the present value, as future cash flows are worth less today.
Can I calculate the value of an annuity with irregular payments?
No, the standard annuity formulas used in this calculator are designed for series of *equal* payments at *regular* intervals. Calculating the value of annuities with irregular payments requires different, more complex methods, often involving summing the present values of each individual cash flow.
What does a negative interest rate imply for annuity value?
Negative interest rates are rare but would mean the value of the annuity decreases over time. For future value, it implies a loss rather than growth. For present value, it would increase the value, as future payments are worth more today than face value.
How is the number of periods calculated?
The number of periods is the total count of payments. It's calculated by multiplying the number of years the annuity runs by the number of payments made per year (Payment Frequency). For example, 10 years of monthly payments result in 120 periods.
Does inflation affect the real value of an annuity?
Yes, significantly. While the nominal value of an annuity is calculated using the formulas above, inflation erodes the purchasing power of that money over time. For retirement planning, it's crucial to consider an annuity's future value in terms of today's purchasing power, often by using a discount rate that incorporates inflation expectations.
What is the difference between an annuity and a perpetuity?
A perpetuity is a special type of annuity that pays out indefinitely (an infinite number of periods). The present value of a perpetuity is calculated simply as P / i (Periodic Payment divided by Periodic Interest Rate), assuming payments are made at the end of each period.
Can this calculator handle annuities with fees?
This calculator uses the inputs you provide directly in the formulas. It does not automatically account for fees or charges inherent in specific financial products. It's essential to input the *net* interest rate (after fees) or adjust your expected payment amounts to reflect any costs associated with a real-world annuity.
Related Tools and Internal Resources
Compound Interest Calculator – Explore how your money grows over time with compounding returns, a key factor in annuity growth.
Loan Amortization Calculator – Understand how loan payments are broken down into principal and interest, similar to how annuity payouts can be analyzed.
Inflation Calculator – Gauge the impact of inflation on the purchasing power of your money over time, crucial for long-term annuity planning.
ROI Calculator – Determine the return on investment for various financial decisions, helping you compare annuity performance against other opportunities.
Annuity vs. IRA – Learn the differences between annuities and Individual Retirement Accounts to make informed retirement saving choices.
// Global variables for Chart.js
var annuityChartInstance = null;
var chartCanvas = document.getElementById('annuityChart').getContext('2d');
function isValidNumber(value, min = -Infinity, max = Infinity) {
var num = parseFloat(value);
return !isNaN(num) && num >= min && num <= max;
}
function displayError(elementId, message, showError) {
var errorElement = document.getElementById(elementId);
if (showError) {
errorElement.textContent = message;
errorElement.style.display = 'block';
} else {
errorElement.textContent = '';
errorElement.style.display = 'none';
}
}
function updateFormLabels() {
var calculationType = document.getElementById('calculationType').value;
var periodPaymentLabel = document.getElementById('periodPaymentLabel');
var periodPaymentHelp = document.getElementById('periodPaymentHelp');
var interestRateLabel = document.getElementById('interestRateLabel');
var numberOfPeriodsLabel = document.getElementById('numberOfPeriodsLabel');
var formulaText = document.getElementById('formulaText');
var paymentFrequencyGroup = document.getElementById('paymentFrequencyGroup');
if (calculationType === 'futureValue') {
periodPaymentLabel.textContent = 'Periodic Payment Amount:';
periodPaymentHelp.textContent = 'The amount paid or received each period (e.g., monthly, yearly).';
interestRateLabel.textContent = 'Annual Interest Rate (%):';
numberOfPeriodsLabel.textContent = 'Number of Periods:';
formulaText.textContent = 'FV = P * [((1 + i)^n – 1) / i] (for Ordinary Annuity) or FV = P * [((1 + i)^n – 1) / i] * (1 + i) (for Annuity Due)';
paymentFrequencyGroup.style.display = 'block';
} else { // presentValue
periodPaymentLabel.textContent = 'Periodic Payment Amount:';
periodPaymentHelp.textContent = 'The amount paid or received each period (e.g., monthly, yearly).';
interestRateLabel.textContent = 'Annual Discount Rate (%):';
numberOfPeriodsLabel.textContent = 'Number of Periods:';
formulaText.textContent = 'PV = P * [(1 – (1 + i)^-n) / i] (for Ordinary Annuity) or PV = P * [(1 – (1 + i)^-n) / i] * (1 + i) (for Annuity Due)';
paymentFrequencyGroup.style.display = 'block';
}
updateNumberOfPeriodsLabel(); // Update help text for number of periods based on frequency
calculateAnnuity(); // Recalculate if type changes
}
function updateNumberOfPeriodsLabel() {
var calculationType = document.getElementById('calculationType').value;
var numberOfPeriodsInput = document.getElementById('numberOfPeriods');
var paymentFrequencySelect = document.getElementById('paymentFrequency');
var numberOfPeriodsLabel = document.getElementById('numberOfPeriodsLabel');
var numberOfPeriodsHelp = document.getElementById('numberOfPeriodsHelp');
var years = parseInt(numberOfPeriodsInput.value) / parseInt(paymentFrequencySelect.value);
if (isNaN(years)) years = 0;
if (calculationType === 'futureValue' || calculationType === 'presentValue') {
numberOfPeriodsLabel.textContent = 'Number of Periods:';
numberOfPeriodsHelp.textContent = 'Total number of payments. For example, 10 years of monthly payments = 120 periods.';
paymentFrequencyGroup.style.display = 'block';
} else {
paymentFrequencyGroup.style.display = 'none';
}
}
function calculateAnnuity() {
// Clear previous errors
displayError('periodPaymentError', '', false);
displayError('interestRateError', '', false);
displayError('numberOfPeriodsError', '', false);
// Get inputs
var calculationType = document.getElementById('calculationType').value;
var periodPayment = parseFloat(document.getElementById('periodPayment').value);
var interestRate = parseFloat(document.getElementById('interestRate').value);
var numberOfPeriods = parseInt(document.getElementById('numberOfPeriods').value);
var paymentFrequency = parseInt(document.getElementById('paymentFrequency').value);
var annuityType = document.getElementById('annuityType').value;
// Validate inputs
var isValid = true;
if (!isValidNumber(periodPayment, 0)) {
displayError('periodPaymentError', 'Please enter a valid non-negative payment amount.', true);
isValid = false;
}
if (!isValidNumber(interestRate, 0, 100)) {
displayError('interestRateError', 'Please enter a valid annual rate between 0% and 100%.', true);
isValid = false;
}
if (!isValidNumber(numberOfPeriods, 1)) {
displayError('numberOfPeriodsError', 'Please enter a valid number of periods (at least 1).', true);
isValid = false;
}
if (!isValidNumber(paymentFrequency, 1)) {
// Should not happen with select, but good practice
isValid = false;
}
if (!isValid) {
resetResults();
return;
}
// Calculations
var periodicInterestRate = interestRate / 100 / paymentFrequency;
var totalPeriods = numberOfPeriods; // Assuming numberOfPeriods already accounts for frequency based on helper text logic. If not, it should be numberOfPeriods * paymentFrequency
var fv, pv, totalPayments, totalInterestOrDiscount;
var calculationResult = {};
if (calculationType === 'futureValue') {
// Future Value calculation
if (annuityType === 'ordinary') {
fv = periodPayment * (Math.pow(1 + periodicInterestRate, totalPeriods) – 1) / periodicInterestRate;
} else { // annuity due
fv = periodPayment * (Math.pow(1 + periodicInterestRate, totalPeriods) – 1) / periodicInterestRate * (1 + periodicInterestRate);
}
totalPayments = periodPayment * totalPeriods;
totalInterestOrDiscount = fv – totalPayments;
calculationResult = {
primaryValue: fv,
intermediate1: totalPayments,
intermediate2: totalInterestOrDiscount,
intermediateLabel1: 'Total Payments Made',
intermediateLabel2: 'Total Interest Earned',
primaryLabel: 'Future Value',
formula: 'FV = P * [((1 + i)^n – 1) / i] * Adjustment (for Ordinary/Due)'
};
} else { // presentValue
// Present Value calculation
if (annuityType === 'ordinary') {
pv = periodPayment * (1 – Math.pow(1 + periodicInterestRate, -totalPeriods)) / periodicInterestRate;
} else { // annuity due
pv = periodPayment * (1 – Math.pow(1 + periodicInterestRate, -totalPeriods)) / periodicInterestRate * (1 + periodicInterestRate);
}
totalPayments = periodPayment * totalPeriods;
totalInterestOrDiscount = pv – totalPayments; // This will be negative, representing the discount
calculationResult = {
primaryValue: pv,
intermediate1: totalPayments,
intermediate2: totalInterestOrDiscount, // Represents the total discount amount
intermediateLabel1: 'Total Payments Received',
intermediateLabel2: 'Total Discount',
primaryLabel: 'Present Value',
formula: 'PV = P * [(1 – (1 + i)^-n) / i] * Adjustment (for Ordinary/Due)'
};
}
// Display results
document.getElementById('primaryResult').textContent = formatCurrency(calculationResult.primaryValue);
document.getElementById('intermediateResult1').textContent = formatCurrency(calculationResult.intermediate1);
document.getElementById('intermediateLabel1').textContent = calculationResult.intermediateLabel1;
document.getElementById('intermediateResult2').textContent = formatCurrency(calculationResult.intermediate2);
document.getElementById('intermediateLabel2').textContent = calculationResult.intermediateLabel2;
// Adjust third intermediate value based on calculation type
if (calculationType === 'futureValue') {
document.getElementById('intermediateResult3').textContent = formatCurrency(interestRate * 100) + '%'; // Display Rate
document.getElementById('intermediateLabel3').textContent = 'Annual Interest Rate';
} else {
document.getElementById('intermediateResult3').textContent = formatCurrency(interestRate) + '%'; // Display Rate
document.getElementById('intermediateLabel3').textContent = 'Annual Discount Rate';
}
document.getElementById('formulaText').textContent = calculationResult.formula;
updateChartAndTable(calculationResult.primaryValue, periodPayment, periodicInterestRate, totalPeriods, annuityType, calculationType);
}
function formatCurrency(amount) {
if (isNaN(amount) || !isFinite(amount)) {
return '$–.–';
}
return '$' + amount.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
function resetResults() {
document.getElementById('primaryResult').textContent = '–';
document.getElementById('intermediateResult1').textContent = '–';
document.getElementById('intermediateLabel1').textContent = '';
document.getElementById('intermediateResult2').textContent = '–';
document.getElementById('intermediateLabel2').textContent = '';
document.getElementById('intermediateResult3').textContent = '–';
document.getElementById('intermediateLabel3').textContent = '';
document.getElementById('formulaText').textContent = 'Select calculation type to see formula.';
// Clear chart and table
if (annuityChartInstance) {
annuityChartInstance.destroy();
annuityChartInstance = null;
}
var tableBody = document.querySelector('#annuityTable tbody');
tableBody.innerHTML = '
Enter values and click Calculate.
';
}
function resetForm() {
document.getElementById('periodPayment').value = '1000';
document.getElementById('interestRate').value = '5';
document.getElementById('numberOfPeriods').value = '10';
document.getElementById('paymentFrequency').value = '12';
document.getElementById('calculationType').value = 'futureValue';
document.getElementById('annuityType').value = 'ordinary';
updateFormLabels();
resetResults();
}
function copyResults() {
var primaryResult = document.getElementById('primaryResult').textContent;
var intermediate1 = document.getElementById('intermediateResult1').textContent + ' (' + document.getElementById('intermediateLabel1').textContent + ')';
var intermediate2 = document.getElementById('intermediateResult2').textContent + ' (' + document.getElementById('intermediateLabel2').textContent + ')';
var intermediate3 = document.getElementById('intermediateResult3').textContent + ' (' + document.getElementById('intermediateLabel3').textContent + ')';
var calculationType = document.getElementById('calculationType').value === 'futureValue' ? 'Future Value' : 'Present Value';
var summary = `Annuity Calculation Results (${calculationType}):\n\n`;
summary += `Primary Result: ${primaryResult}\n`;
summary += `Intermediate 1: ${intermediate1}\n`;
summary += `Intermediate 2: ${intermediate2}\n`;
summary += `Intermediate 3: ${intermediate3}\n`;
var tempTextArea = document.createElement('textarea');
tempTextArea.value = summary;
document.body.appendChild(tempTextArea);
tempTextArea.select();
try {
document.execCommand('copy');
alert('Results copied to clipboard!');
} catch (err) {
alert('Failed to copy results.');
}
document.body.removeChild(tempTextArea);
}
// Charting Logic
function updateChartAndTable(finalValue, payment, periodicRate, periods, annuityType, calcType) {
var tableBody = document.querySelector('#annuityTable tbody');
tableBody.innerHTML = "; // Clear previous table data
var yearlyData = [];
var currentBalance = 0;
var totalPaymentsMade = 0;
var totalInterestEarned = 0;
var effectivePeriods = periods; // Use the provided total periods
var freq = document.getElementById('paymentFrequency').value;
var paymentsPerYear = parseInt(freq);
// Initial balance for FV depends on annuity type
if (calcType === 'futureValue') {
currentBalance = (annuityType === 'due') ? payment : 0;
totalPaymentsMade = (annuityType === 'due') ? payment : 0;
} else { // Present Value – calculations are different for table breakdown
// Present value table breakdown is tricky and less intuitive yearly for PV.
// We'll focus the table on FV and populate with placeholders for PV for simplicity.
// A true PV table would show discounted values which is complex.
tableBody.innerHTML = '
Yearly breakdown for Present Value is complex and not displayed here. Focus is on final PV calculation.
';
return; // Exit if PV, as table logic is focused on FV growth
}
// Populate Table and gather data for chart (yearly breakdown)
var yearsToDisplay = Math.min(10, Math.ceil(periods / paymentsPerYear)); // Display up to 10 years or fewer if total periods < 10*freq
if (periods < paymentsPerYear) yearsToDisplay = 1; // Show at least 1 year if less than a full year
for (var year = 1; year <= yearsToDisplay; year++) {
var startOfYearBalance = currentBalance;
var interestThisYear = 0;
var paymentsThisYear = 0;
var periodsInYear = Math.min(paymentsPerYear, Math.max(0, periods – (year – 1) * paymentsPerYear));
for (var p = 0; p yearsToDisplay * paymentsPerYear) {
var row = tableBody.insertRow();
row.innerHTML = `
… further periods …
`;
}
// Update Chart
if (annuityChartInstance) {
annuityChartInstance.destroy();
}
var labels = yearlyData.map(d => `Year ${d.year}`);
var principalSeries = yearlyData.map(d => d.payment); // Sum of payments up to that year
var interestSeries = yearlyData.map(d => d.interest); // Sum of interest earned up to that year
// Recalculate cumulative principal and interest for accurate chart series
var cumulativePrincipal = 0;
var cumulativeInterest = 0;
var cumulativePrincipalSeries = [];
var cumulativeInterestSeries = [];
yearlyData.forEach(function(data) {
cumulativePrincipal += data.payment;
cumulativeInterest += data.interest;
cumulativePrincipalSeries.push(cumulativePrincipal);
cumulativeInterestSeries.push(cumulativeInterest);
});
annuityChartInstance = new Chart(chartCanvas, {
type: 'bar', // Use bar chart for better visualization of components
data: {
labels: labels,
datasets: [{
label: 'Total Payments Made',
data: cumulativePrincipalSeries,
backgroundColor: 'rgba(0, 74, 153, 0.6)', // Primary color
borderColor: 'rgba(0, 74, 153, 1)',
borderWidth: 1,
type: 'line', // Can overlay lines if needed
fill: false,
yAxisID: 'y-axis-1'
}, {
label: 'Total Interest Earned',
data: cumulativeInterestSeries,
backgroundColor: 'rgba(40, 167, 69, 0.6)', // Success color
borderColor: 'rgba(40, 167, 69, 1)',
borderWidth: 1,
type: 'line',
fill: false,
yAxisID: 'y-axis-1'
}]
},
options: {
responsive: true,
maintainAspectRatio: false,
scales: {
xAxes: [{
stacked: false, // Set to false for line overlay
gridLines: {
display: false
}
}],
yAxes: [{
id: 'y-axis-1',
scaleLabel: {
display: true,
labelString: 'Amount ($)'
},
stacked: false, // Set to false for line overlay
ticks: {
beginAtZero: true,
callback: function(value) {
return '$' + value.toFixed(0).replace(/\B(?=(\d{3})+(?!\d))/g, ',');
}
}
}]
},
tooltips: {
callbacks: {
label: function(tooltipItem, data) {
var label = data.datasets[tooltipItem.datasetIndex].label || ";
if (label) {
label += ': ';
}
label += '$' + Number(tooltipItem.yLabel).toFixed(2).replace(/\B(?=(\d{3})+(?!\d))/g, ',');
return label;
}
}
}
}
});
}
// FAQ Toggle Logic
function toggleFaq(element) {
var content = element.nextElementSibling;
if (content.style.display === "block") {
content.style.display = "none";
} else {
content.style.display = "block";
}
}
// Initial setup
document.addEventListener('DOMContentLoaded', function() {
updateFormLabels();
calculateAnnuity(); // Calculate with default values on load
});
// Polyfill for execCommand('copy') for older browsers if needed
// Not strictly required by prompt but good practice
if (!document.execCommand) {
document.execCommand = function(command, showUI, value) {
console.warn("execCommand is not supported in this browser.");
return false;
};
}