Accurately measure your investment performance considering the timing and size of cash flows.
Investment Performance Calculator
Enter the starting value of your investment.
Enter the ending value of your investment.
Enter the total duration of the investment in years.
Cash Flows
Enter amount (positive for additions, negative for withdrawals) and date.
Calculation Results
Dollar Weighted Rate of Return:
—%
(Internal Rate of Return)
—
—
—
—
Formula Used (Internal Rate of Return – IRR): The Dollar Weighted Rate of Return (often calculated as IRR) finds the discount rate that makes the net present value of all cash flows (initial investment, final value, and intermediate cash flows) equal to zero. This is an iterative process or can be approximated.
Investment Value Over Time (Simulated)
This chart simulates the investment's growth, incorporating cash flows and the calculated return.
Cash Flow Summary
Date
Amount
Net Effect
Cumulative Investment
Calculated Return
Summary of all cash flows and their impact on the investment's performance.
What is Dollar Weighted Rate of Return?
The dollar weighted rate of return, often synonymous with the Internal Rate of Return (IRR) in investment contexts, is a crucial metric for evaluating the performance of an investment portfolio, especially when there are multiple cash inflows and outflows over time. Unlike the Time-Weighted Rate of Return (TWRR), which measures the compound growth rate of a hypothetical $1 investment, the dollar weighted rate of return emphasizes the actual monetary performance experienced by the investor. It takes into account not only the investment's returns but also the timing and magnitude of the investor's contributions and withdrawals.
Who Should Use It?
Individual Investors: Anyone who makes deposits or withdrawals from their investment accounts (e.g., retirement funds, brokerage accounts) throughout the year needs to understand their dollar weighted rate of return to see how their personal cash flow actions affected their overall investment outcomes.
Portfolio Managers: When managing client accounts with varying cash flow activities, this metric helps assess the effectiveness of investment strategies considering the client's direct involvement.
Financial Advisors: To provide clients with a realistic picture of their investment growth, reflecting their specific financial activities.
Common Misconceptions:
It's the same as TWRR: While related, they measure different aspects. TWRR isolates the manager's performance, ignoring cash flow timing. Dollar weighted return reflects the investor's actual experience.
It only considers the start and end values: This is incorrect. The core of the dollar weighted return calculation is its sensitivity to the timing and size of all cash flows.
Higher is always better, regardless of cash flows: A high dollar weighted return could be influenced by favorable cash flow timing rather than just superior investment selection.
Dollar Weighted Rate of Return Formula and Mathematical Explanation
The dollar weighted rate of return is essentially the Internal Rate of Return (IRR) of an investment. The IRR is the discount rate at which the Net Present Value (NPV) of all cash flows from a particular investment equals zero. In simpler terms, it's the effective rate of return that makes the present value of all money taken out of the investment equal to the present value of all money put into the investment.
The fundamental equation is:
0 = Σ [ CFt / (1 + R)^t ]
Where:
CFt = Net cash flow during period t
R = Dollar weighted rate of return (the variable we solve for)
t = Time period
For a practical investment scenario with an initial investment, a final value, and intermediate cash flows, the equation expands. Let's consider an investment over 'n' periods (usually years, but can be months or days). The cash flows are adjusted for their timing. The final value is treated as a cash inflow at the end of the period.
Solving this equation for 'R' directly is often mathematically complex, especially with numerous cash flows. Therefore, numerical methods (like the IRR function in spreadsheets or financial calculators) are typically used. These methods iteratively test different values of 'R' until the equation holds true.
Variable Explanations
Variable
Meaning
Unit
Typical Range
Initial Investment
The starting amount of capital invested at the beginning of the period.
Currency (e.g., USD, EUR)
Positive value
Final Investment Value
The total market value of the investment at the end of the period.
Currency
Non-negative value
Intermediate Cash Flows
Any deposits (inflows, positive) or withdrawals (outflows, negative) made during the investment period.
Currency
Any real number (positive or negative)
Timing of Cash Flows
The specific dates on which cash flows occurred relative to the start and end of the measurement period. Crucial for dollar weighting.
Date / Time
Dates within the investment period
Investment Period
The total duration over which the return is measured (e.g., years, months).
Time units (e.g., Years)
Positive value
R (Dollar Weighted Rate of Return)
The effective annualized rate of return that accounts for cash flow timing and amounts.
Percentage (%)
Typically -100% to very high positive percentages
Practical Examples (Real-World Use Cases)
Example 1: Growing an Investment Portfolio
Sarah starts investing with an initial amount and adds funds periodically while letting her gains accumulate.
Initial Investment: $10,000 on January 1, 2021
Investment Period: 3 years (ends December 31, 2023)
Cash Flows:
$500 added on July 1, 2021
$1,000 added on January 1, 2022
$750 added on August 15, 2023
Final Investment Value: $15,500 on December 31, 2023
Calculation: Using a dollar weighted rate of return calculator (or IRR function), we input these values. The calculator will find the rate 'R' that balances the present values of all cash movements.
Hypothetical Results:
Dollar Weighted Rate of Return: 7.85%
Total Investment Gain/Loss: $3,250 (Calculated as $15,500 – $10,000 – $500 – $1,000 – $750)
Weighted Average Cash Inflow: ~$12,000 (This is a conceptual average, the IRR calculation uses precise timings)
Weighted Average Cash Outflow: $0 (No withdrawals)
Interpretation: Sarah achieved an effective annual return of approximately 7.85% on her invested capital, considering her consistent additions to the portfolio. This metric reflects her actual wealth accumulation.
Example 2: Managing a Retirement Account with Withdrawals
John is retired and draws income from his investment account, while the account also experiences market fluctuations.
Initial Investment Value (start of year): $200,000 on January 1, 2023
Investment Period: 1 year (ends December 31, 2023)
Cash Flows:
$3,000 withdrawn on March 1, 2023
$4,000 withdrawn on September 1, 2023
$1,500 contribution on June 1, 2023
Final Investment Value: $195,000 on December 31, 2023
Calculation: Inputting these figures into the calculator.
Hypothetical Results:
Dollar Weighted Rate of Return: -1.50%
Total Investment Gain/Loss: -$1,500 (Calculated as $195,000 – $200,000 – $3,000 – $4,000 + $1,500)
Weighted Average Cash Inflow: ~$1,500
Weighted Average Cash Outflow: ~$6,750 (Reflects the timing and amounts withdrawn)
Interpretation: Despite the market, John's dollar weighted return was -1.50%. This indicates that the withdrawals, combined with market performance, led to a slight decrease in his overall investment value over the year. The negative return reflects both market conditions and the impact of taking money out.
How to Use This Dollar Weighted Rate of Return Calculator
Our calculator simplifies the process of determining your investment's dollar weighted rate of return. Follow these steps for accurate results:
Enter Initial Investment: Input the exact amount you started with at the beginning of your investment period.
Enter Final Investment Value: Provide the total market value of your investment at the end of the measurement period.
Specify Investment Period: Enter the duration of the investment in years (e.g., 1, 5, 10).
Add Cash Flows:
Click "Add Another Cash Flow" for each deposit or withdrawal made during the period.
For each cash flow, enter the Amount. Use positive numbers for contributions (money added) and negative numbers for withdrawals (money taken out).
Select the exact Date for each cash flow. Accuracy here is critical for the dollar weighting.
Calculate: Click the "Calculate Return" button.
Review Results: The calculator will display:
The primary Dollar Weighted Rate of Return (as a percentage).
Total Investment Gain/Loss: The net change in your investment value, adjusted for cash flows.
Weighted Average Cash Inflow/Outflow: These provide context but are secondary to the main IRR calculation.
Approximate Time-Weighted Return: A related metric for comparison.
Understand the Formula: Read the brief explanation of the IRR formula to grasp how the calculation works.
Visualize: Examine the chart simulating investment value and the cash flow summary table for detailed insights.
Copy or Reset: Use the "Copy Results" button to save your findings or "Reset" to start a new calculation.
Decision-Making Guidance: Use the calculated dollar weighted rate of return to compare the performance of different investments or strategies, especially when cash flow activities differ significantly. A higher rate generally indicates better performance relative to the capital invested and withdrawn. Remember to consider your financial goals and risk tolerance when interpreting these results.
Key Factors That Affect Dollar Weighted Rate of Return Results
Several factors significantly influence the calculated dollar weighted rate of return. Understanding these helps in interpreting the results accurately:
Timing of Cash Flows: This is the most critical factor differentiating dollar-weighted from time-weighted returns. Money invested just before a period of high returns positively impacts the dollar-weighted return more than money invested after the gains have occurred. Conversely, withdrawals made just before a market downturn have a less negative impact than withdrawals made after the loss.
Magnitude of Cash Flows: Larger cash inflows (contributions) made during periods of strong performance will boost the dollar-weighted return. Similarly, large outflows (withdrawals) during periods of poor performance can significantly depress the metric. The "weight" of the return is directly proportional to the amount of money invested.
Overall Investment Performance (Market Returns): The underlying growth or decline in the value of the investments themselves is fundamental. Positive market returns increase the value, while negative returns decrease it. The dollar-weighted return captures how well the portfolio grew relative to the capital invested and withdrawn.
Investment Strategy and Asset Allocation: The choice of assets (stocks, bonds, real estate) and how they are allocated impacts the potential returns and volatility. A riskier allocation might yield higher potential returns but also greater fluctuations, affecting the dollar-weighted outcome based on cash flow timing.
Fees and Expenses: Management fees, trading costs, and other expenses reduce the net return on investment. These are implicitly accounted for in the final value and cash flows, thus impacting the dollar-weighted rate of return. Higher fees lead to lower overall returns.
Taxes: Capital gains taxes, dividend taxes, and income taxes reduce the amount of money an investor ultimately keeps. While not always directly input into basic calculators, taxes affect the *realized* return and the final value, influencing the dollar-weighted calculation.
Inflation: Although not directly part of the IRR calculation itself, inflation erodes the purchasing power of returns. A high dollar-weighted return might still result in a low *real* return if inflation is significantly higher than the nominal rate. It's crucial for context.
Frequently Asked Questions (FAQ)
What's the difference between Dollar Weighted Rate of Return and Time Weighted Rate of Return?
The Dollar Weighted Rate of Return (or IRR) measures the actual return an investor experiences, influenced by the timing and size of their cash flows. The Time Weighted Rate of Return (TWRR) measures the compound growth rate of a hypothetical investment, isolating the investment manager's performance by removing the impact of cash flows.
Why is the timing of cash flows so important for the dollar weighted return?
Money invested earlier has more time to earn returns, and money withdrawn later has less impact on the overall performance calculation. The dollar weighted method assigns more "weight" to cash flows that are present for longer periods or are larger in magnitude during specific market conditions.
Can the dollar weighted rate of return be negative?
Yes, absolutely. If the investment loses value and/or the investor makes significant withdrawals during periods of loss, the dollar weighted rate of return can be negative. This reflects a loss in the investor's actual capital.
Does this calculator handle monthly cash flows?
Our calculator is designed primarily for annual periods for simplicity, but the underlying IRR principle can be adapted for any period (monthly, quarterly). For precise monthly calculations, you would need to adjust the 't' (time) variable accordingly, often by using months instead of years and solving for a monthly IRR, then annualizing it.
What if I had multiple years of data?
For multi-year calculations, you should ideally calculate the return for each year separately using the dollar weighted method, or use a financial calculator/software capable of handling longer IRR calculations with all cash flows sequentially. This calculator is best suited for a defined start and end period.
How does this differ from a simple average return?
A simple average return does not account for the timing or size of cash flows, nor does it account for compounding. The dollar weighted return (IRR) provides a more accurate picture by considering all these factors, giving a single, annualized rate that reflects the investor's experience.
Is the dollar weighted return useful for comparing mutual funds?
Not directly for comparing fund managers. Mutual fund performance is typically reported using Time-Weighted Rate of Return (TWRR) to isolate manager skill. The dollar weighted return is most useful for evaluating YOUR specific investment experience within an account, considering your actions.
What does 'Net Effect' mean in the cash flow table?
The 'Net Effect' in the table shows the cash flow amount itself. Positive values are additions (inflows), and negative values are withdrawals (outflows). The 'Cumulative Investment' column shows the running total of all money put into and taken out of the investment over time.
Foundational knowledge for making informed decisions about your money.
var cashFlowCounter = 1;
var initialInvestmentInput = document.getElementById('initialInvestment');
var finalValueInput = document.getElementById('finalValue');
var periodInYearsInput = document.getElementById('periodInYears');
var resultsDiv = document.getElementById('results');
var dollarWeightedReturnSpan = document.getElementById('dollarWeightedReturn');
var totalGainLossDiv = document.getElementById('totalGainLoss');
var weightedAvgInflowDiv = document.getElementById('weightedAvgInflow');
var weightedAvgOutflowDiv = document.getElementById('weightedAvgOutflow');
var timeWeightedReturnApproxSpan = document.getElementById('timeWeightedReturnApprox');
var cashFlowTableBody = document.querySelector('#cashFlowTable tbody');
var returnChartCanvas = document.getElementById('returnChart');
var ctx; // Chart context
var myChart; // Chart instance
// Initialize chart context if canvas exists
if (returnChartCanvas) {
ctx = returnChartCanvas.getContext('2d');
}
function addCashFlow() {
cashFlowCounter++;
var cashFlowsList = document.getElementById('cashFlowsList');
var newCashFlowDiv = document.createElement('div');
newCashFlowDiv.className = 'input-group cash-flow-item';
newCashFlowDiv.innerHTML = `
Enter amount (positive for additions, negative for withdrawals) and date.
`;
cashFlowsList.appendChild(newCashFlowDiv);
}
function removeCashFlow(button) {
var cashFlowItem = button.closest('.cash-flow-item');
cashFlowItem.remove();
// Re-calculate after removal
calculateReturn();
// Update counter display if needed (optional, for visual clarity)
updateCashFlowLabels();
}
function updateCashFlowLabels() {
var cashFlowItems = document.querySelectorAll('#cashFlowsList .cash-flow-item');
cashFlowItems.forEach(function(item, index) {
var label = item.querySelector('label');
if (label) {
label.textContent = `Cash Flow ${index + 1}`;
}
});
cashFlowCounter = cashFlowItems.length; // Reset counter to the current number of items
}
function validateInput(value, id, min, max) {
var errorElement = document.getElementById(id + 'Error');
var inputElement = document.getElementById(id);
errorElement.style.display = 'none';
inputElement.classList.remove('input-error');
inputElement.classList.remove('input-success');
if (value === ") {
errorElement.textContent = 'This field cannot be empty.';
errorElement.style.display = 'block';
inputElement.classList.add('input-error');
return false;
}
var numValue = parseFloat(value);
if (isNaN(numValue)) {
errorElement.textContent = 'Please enter a valid number.';
errorElement.style.display = 'block';
inputElement.classList.add('input-error');
return false;
}
if (min !== undefined && numValue max) {
errorElement.textContent = `Value cannot exceed ${max}.`;
errorElement.style.display = 'block';
inputElement.classList.add('input-error');
return false;
}
inputElement.classList.add('input-success');
return true;
}
function validateDate(dateString, id) {
var errorElement = document.getElementById(id + 'Error'); // Assuming date inputs might share IDs or need specific error divs.
var inputElement = document.getElementById(id); // Or find the input element if ID is dynamic.
errorElement.style.display = 'none';
inputElement.classList.remove('input-error');
inputElement.classList.remove('input-success');
if (!dateString) {
// Allow empty dates if not mandatory for calculation, or handle error
return true; // Or display error if date is mandatory
}
// Basic date validation (can be more robust)
var dateRegex = /^\d{4}-\d{2}-\d{2}$/;
if (!dateRegex.test(dateString)) {
// errorElement.textContent = 'Invalid date format. Use YYYY-MM-DD.';
// errorElement.style.display = 'block';
// inputElement.classList.add('input-error');
return false; // var calculation handle potentially invalid date logic
}
inputElement.classList.add('input-success');
return true;
}
function calculateReturn() {
var initialInvestment = parseFloat(initialInvestmentInput.value);
var finalValue = parseFloat(finalValueInput.value);
var periodInYears = parseFloat(periodInYearsInput.value);
var validInputs = true;
validInputs &= validateInput(initialInvestmentInput.value, 'initialInvestment', 0);
validInputs &= validateInput(finalValueInput.value, 'finalValue', 0);
validInputs &= validateInput(periodInYearsInput.value, 'periodInYears', 0.01); // Period must be positive
var cashFlows = [];
var cashFlowElements = document.querySelectorAll('#cashFlowsList .cash-flow-item');
var allCashFlowsValid = true;
cashFlowElements.forEach(function(cfElement, index) {
var amountInput = cfElement.querySelector('.cash-flow-amount');
var dateInput = cfElement.querySelector('.cash-flow-date');
var errorDiv = cfElement.querySelector('.error-message');
var amount = parseFloat(amountInput.value);
var dateStr = dateInput.value;
// Reset previous errors for this cash flow
errorDiv.style.display = 'none';
amountInput.classList.remove('input-error');
dateInput.classList.remove('input-error');
if (isNaN(amount)) {
errorDiv.textContent = 'Invalid amount.';
errorDiv.style.display = 'block';
amountInput.classList.add('input-error');
allCashFlowsValid = false;
}
// Basic date validation
var dateObj = null;
if (dateStr) {
dateObj = new Date(dateStr);
if (isNaN(dateObj.getTime())) {
errorDiv.textContent = 'Invalid date.';
errorDiv.style.display = 'block';
dateInput.classList.add('input-error');
allCashFlowsValid = false;
} else {
dateInput.classList.add('input-success');
}
} else {
// If date is required, uncomment below
// errorDiv.textContent = 'Date is required.';
// errorDiv.style.display = 'block';
// dateInput.classList.add('input-error');
// allCashFlowsValid = false;
}
cashFlows.push({
amount: amount,
date: dateObj,
element: cfElement // Store element for easier access
});
});
if (!validInputs || !allCashFlowsValid) {
resultsDiv.style.display = 'none';
return;
}
resultsDiv.style.display = 'block';
// Sort cash flows by date for correct calculation
cashFlows.sort(function(a, b) {
return a.date – b.date;
});
// — Core Calculation Logic for Dollar Weighted Return (IRR Approximation) —
// This is a simplified iterative approach. For complex cases, libraries or
// dedicated financial functions are better.
// We'll use a simplified IRR approximation: find R where NPV is close to 0.
var startDate = new Date(Date.UTC(new Date().getFullYear() – periodInYears, 0, 1)); // Simplified start date for period calculation
if (periodInYearsInput.value > 0) {
// Attempt to derive a more accurate start date based on the earliest cash flow if provided
var earliestDate = null;
if (cashFlows.length > 0 && cashFlows[0].date) {
earliestDate = cashFlows[0].date;
}
if(earliestDate && earliestDate 0) { // Approximate end date
allDates.push(new Date(Date.UTC(startDate.getUTCFullYear() + periodInYears, startDate.getUTCMonth(), startDate.getUTCDate())));
}
allDates.sort((a, b) => a – b);
startDate = allDates[0] || startDate;
}
}
var endDate = new Date(Date.UTC(startDate.getUTCFullYear() + periodInYears, startDate.getUTCMonth(), startDate.getUTCDate()));
var netCashFlows = [];
netCashFlows.push({ amount: -initialInvestment, date: startDate }); // Initial investment as negative cash flow
cashFlows.forEach(function(cf) {
if(cf.date && cf.amount !== null && !isNaN(cf.amount)) {
// Adjust amount sign for inflows/outflows if needed based on convention
// Here, positive amount is inflow, negative is outflow
netCashFlows.push({ amount: cf.amount, date: cf.date });
}
});
netCashFlows.push({ amount: finalValue, date: endDate }); // Final value as positive cash flow
// Sort all cash flows chronologically including start and end
netCashFlows.sort(function(a, b) {
return a.date – b.date;
});
// Remove duplicate dates by summing amounts for the same date
var consolidatedNetCashFlows = [];
if (netCashFlows.length > 0) {
consolidatedNetCashFlows.push(netCashFlows[0]);
for (var i = 1; i < netCashFlows.length; i++) {
if (netCashFlows[i].date.getTime() === netCashFlows[i-1].date.getTime()) {
consolidatedNetCashFlows[consolidatedNetCashFlows.length – 1].amount += netCashFlows[i].amount;
} else {
consolidatedNetCashFlows.push(netCashFlows[i]);
}
}
}
// Calculate IRR using an iterative approximation method (Newton-Raphson or similar)
// This is a simplified placeholder. A robust IRR function is complex.
// A common approximation involves trial and error or financial library functions.
// For this example, we'll use a simplified approach that might work for typical inputs.
// Try a range of rates
var irr = 0;
var maxIterations = 100;
var precision = 0.00001;
var guess = 0.1; // Initial guess for IRR
function calculateNPV(rate, flows) {
var npv = 0;
for (var i = 0; i < flows.length; i++) {
var daysDiff = (flows[i].date.getTime() – flows[0].date.getTime()) / (1000 * 60 * 60 * 24);
var yearsDiff = daysDiff / 365.25; // Account for leap years
if (rate === -1) { // Handle -100% rate case to avoid division by zero
npv += flows[i].amount; // Treat as simple sum if rate is -100%
} else {
npv += flows[i].amount / Math.pow(1 + rate, yearsDiff);
}
}
return npv;
}
// Simple bisection method for IRR approximation
var lowRate = -0.999; // Lower bound for rate (e.g., -99.9%)
var highRate = 5.0; // Upper bound for rate (e.g., 500%)
var rateIncrement = 0.01; // Step for checking rates
var foundIrr = false;
for (var rate = lowRate; rate <= highRate; rate += rateIncrement) {
var npvHigh = calculateNPV(rate, consolidatedNetCashFlows);
var npvLow = calculateNPV(rate – rateIncrement, consolidatedNetCashFlows);
if (npvHigh 0) { // Found a crossover point where NPV goes from positive to negative
// Interpolate for better precision
var fraction = npvLow / (npvLow – npvHigh);
irr = rate – rateIncrement + (rateIncrement * fraction);
foundIrr = true;
break;
}
// Handle edge case where NPV is exactly 0 at a checked rate
if (Math.abs(npvHigh) < precision) {
irr = rate;
foundIrr = true;
break;
}
}
// If iterative search failed, use a default or indicate error
if (!foundIrr) {
// Try Newton-Raphson if bisection failed or needs refinement
var currentRate = guess;
for (var iter = 0; iter < maxIterations; iter++) {
var npv = calculateNPV(currentRate, consolidatedNetCashFlows);
var derivative = (calculateNPV(currentRate + precision, consolidatedNetCashFlows) – npv) / precision;
if (Math.abs(derivative) < 1e-10) { // Avoid division by zero
break;
}
var nextRate = currentRate – npv / derivative;
if (Math.abs(nextRate – currentRate) 1) {
// This formula assumes the calculated IRR is for the *entire* period.
// To annualize, we use: (1 + Total_Return)^(1/Years) – 1
// Where Total_Return is derived from the NPV calculation.
// A simpler, though less precise method for IRR context:
// annualizedIrr = Math.pow(1 + irr, 1 / periodInYears) – 1;
// However, since IRR *is* the rate that makes NPV zero, and it's often *intended* to be annualized,
// we'll stick with the calculated IRR for now, assuming it represents the effective annual rate needed.
// For a true multi-year IRR, the time periods in the NPV calculation must be precise.
annualizedIrr = irr; // Keeping it as calculated IRR, which is often interpreted as annualized rate directly.
} else if (periodInYears 0) totalCashIn += cf.amount;
if (cf.amount 0) ? (Math.pow(1 + annualizedIrr, periodInYears) – 1) * 100 : 0; // TWRR based on annualized IRR assumption
// Display Results
dollarWeightedReturnSpan.textContent = (annualizedIrr * 100).toFixed(2);
totalGainLossDiv.textContent = '$' + totalGainLoss.toFixed(2);
weightedAvgInflowDiv.textContent = '$' + totalCashIn.toFixed(2);
weightedAvgOutflowDiv.textContent = '$' + Math.abs(totalCashOut).toFixed(2); // Show as positive value
timeWeightedReturnApproxSpan.textContent = (effectiveTWRR).toFixed(2) + '%'; // Using the approximated TWRR
// Populate Table
populateCashFlowTable(initialInvestment, cashFlows, finalValue, startDate, endDate);
// Update Chart
updateChart(consolidatedNetCashFlows, initialInvestment, finalValue, annualizedIrr, startDate, endDate);
}
function populateCashFlowTable(initialInvestment, cashFlows, finalValue, startDate, endDate) {
var html = ";
var cumulativeInvestment = initialInvestment;
var currentDate = startDate;
var lastDate = startDate; // Initialize lastDate
// Add initial investment row
html += `
${startDate.toISOString().split('T')[0]}
-$${initialInvestment.toFixed(2)}
Initial Investment
$${cumulativeInvestment.toFixed(2)}
–
`;
cashFlows.forEach(function(cf) {
if (cf.date && !isNaN(cf.amount)) {
var date = cf.date;
var timeDiff = date.getTime() – lastDate.getTime();
var daysDiff = timeDiff / (1000 * 60 * 60 * 24);
var yearsDiff = daysDiff / 365.25;
// Approximate return during this interval (simplified)
// This is tricky without knowing the exact IRR for each sub-period.
// We'll approximate using the overall annualized IRR.
var intervalReturn = 0;
if (yearsDiff > 0 && parseFloat(dollarWeightedReturnSpan.textContent) > -100) { // Ensure valid rate
var rate = parseFloat(dollarWeightedReturnSpan.textContent) / 100;
intervalReturn = (cumulativeInvestment * Math.pow(1 + rate, yearsDiff)) – cumulativeInvestment;
}
cumulativeInvestment += cf.amount; // Update cumulative investment BEFORE adding final value
var netEffect = cf.amount > 0 ? `+$${cf.amount.toFixed(2)}` : `-$${Math.abs(cf.amount).toFixed(2)}`;
var description = cf.amount > 0 ? "Contribution" : "Withdrawal";
html += `
`;
lastDate = date; // Update lastDate
}
});
// Add final value row
var timeDiff = endDate.getTime() – lastDate.getTime();
var daysDiff = timeDiff / (1000 * 60 * 60 * 24);
var yearsDiff = daysDiff / 365.25;
var finalIntervalReturn = 0;
if (yearsDiff > 0 && parseFloat(dollarWeightedReturnSpan.textContent) > -100) {
var rate = parseFloat(dollarWeightedReturnSpan.textContent) / 100;
finalIntervalReturn = (cumulativeInvestment * Math.pow(1 + rate, yearsDiff)) – cumulativeInvestment;
}
// Ensure final value makes sense relative to cumulative investment before final gain/loss.
// The total gain/loss already calculated is more direct. This is for table context.
html += `