function calculateStockReturn() {
// 1. Get input values
var buyPrice = parseFloat(document.getElementById('buyPrice').value);
var sellPrice = parseFloat(document.getElementById('sellPrice').value);
var numShares = parseFloat(document.getElementById('numShares').value);
var divPerShare = parseFloat(document.getElementById('divPerShare').value);
var holdingPeriod = parseFloat(document.getElementById('holdingPeriod').value);
// 2. Validation
if (isNaN(buyPrice) || isNaN(sellPrice) || isNaN(numShares)) {
alert("Please enter valid numbers for Prices and Number of Shares.");
return;
}
// Handle empty dividend field as 0
if (isNaN(divPerShare)) {
divPerShare = 0;
}
// 3. Perform Calculations
var initialInvestment = buyPrice * numShares;
var finalMarketValue = sellPrice * numShares;
var totalDividends = divPerShare * numShares;
var capitalGain = finalMarketValue – initialInvestment;
var totalProfit = capitalGain + totalDividends;
// Return on Investment (ROI) Formula: (Net Profit / Cost of Investment) * 100
var returnPercent = (totalProfit / initialInvestment) * 100;
// Annualized Return (CAGR) Formula: ((Final Value including Divs / Initial Value) ^ (1/n)) – 1
var annualizedReturn = 0;
var showAnnualized = false;
if (!isNaN(holdingPeriod) && holdingPeriod > 0) {
var totalEndValue = finalMarketValue + totalDividends;
var ratio = totalEndValue / initialInvestment;
annualizedReturn = (Math.pow(ratio, 1 / holdingPeriod) – 1) * 100;
showAnnualized = true;
}
// 4. Update the DOM
document.getElementById('resInitial').textContent = "$" + initialInvestment.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resEnding').textContent = "$" + finalMarketValue.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resDividends').textContent = "$" + totalDividends.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
// Color coding for gains/losses
var capGainEl = document.getElementById('resCapitalGain');
capGainEl.textContent = "$" + capitalGain.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
capGainEl.style.color = capitalGain >= 0 ? "#27ae60" : "#c0392b";
var totalProfitEl = document.getElementById('resTotalProfit');
totalProfitEl.textContent = "$" + totalProfit.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
totalProfitEl.style.color = totalProfit >= 0 ? "#27ae60" : "#c0392b";
var percentEl = document.getElementById('resReturnPercent');
percentEl.textContent = returnPercent.toFixed(2) + "%";
percentEl.style.color = returnPercent >= 0 ? "#27ae60" : "#c0392b";
// Handle Annualized Row Visibility
var annRow = document.getElementById('annualizedRow');
if (showAnnualized) {
annRow.style.display = 'flex';
var annEl = document.getElementById('resAnnualized');
annEl.textContent = annualizedReturn.toFixed(2) + "%";
annEl.style.color = annualizedReturn >= 0 ? "#27ae60" : "#c0392b";
} else {
annRow.style.display = 'none';
}
// Show results area
document.getElementById('resultsArea').style.display = 'block';
}
How to Calculate Rate of Return on Stock with Dividends
Calculating the true performance of a stock investment requires more than just looking at the price change. Many investors focus solely on capital gains (the increase in stock price) but neglect the significant impact of dividends. To accurately measure your profitability, you must calculate the Total Return.
The "Total Return" formula accounts for both the appreciation in the stock's price and any income generated from dividends during the holding period. This gives a holistic view of how your investment has performed.
The Stock Total Return Formula
The basic formula for calculating the rate of return on a stock with dividends is:
Selling Price: The current market value or the price at which you sold the stock.
Purchase Price: The price you originally paid for the stock.
Total Dividends: The sum of all dividend payments received per share during the holding period.
Example Calculation
Let's look at a realistic example to see how this works in practice.
You bought 100 shares of "Company XYZ" at $50.00 per share.
After 2 years, the stock price rises to $60.00.
During those 2 years, the company paid out $2.00 in dividends per share.
Step 1: Calculate Capital Gain
($60 – $50) = $10 profit per share from price appreciation.
Step 2: Add Dividends
$10 (Capital Gain) + $2 (Dividends) = $12 Total Gain per share.
Step 3: Calculate Percentage Return
($12 Total Gain / $50 Initial Cost) × 100 = 24% Total Return.
Note: Without including dividends, your return would only appear to be 20%. The dividends added an extra 4% to your bottom line, highlighting why dividend-inclusive calculations are vital.
Annualized Return (CAGR)
If you have held a stock for more than one year, the Total Return percentage can be misleading because it doesn't account for time. A 24% return over 2 years is different from a 24% return over 10 years. To standardize this, we use the Annualized Return or Compound Annual Growth Rate (CAGR).
CAGR = [ (Ending Value + Total Dividends) / Beginning Value ] (1 / Number of Years) – 1
Using the example above over a 2-year period, the annualized return would be approximately 11.35% per year, rather than just dividing the total return by 2.
Why Dividends Matter for ROI
Dividends act as a cushion during market downturns. Even if a stock's price stays flat or drops slightly, high dividend yields can ensure a positive rate of return. When calculating your portfolio's performance, always verify if your brokerage displays "Price Return" (excluding dividends) or "Total Return" (including dividends), as the difference can be substantial over long periods.