Total Return = (Ending Price − Starting Price + Dividends Received) ÷ Starting Price × 100. It captures both capital appreciation and dividend income. Most people quote only price appreciation but ignore dividends — total return is the honest measure for long holdings.

CAGR (Compound Annual Growth Rate) = (Ending ÷ Starting)^(1/years) − 1. It's the smoothed annual rate that produces the same final result as the actual volatile path. Average return overstates real performance because it doesn't penalize losses correctly. A stock that goes +50% then −50% has 0% average return but the actual outcome is −25% (CAGR ≈ −13%).

Always — dividends contribute 2–4% per year on average for the S&P 500, and reinvested dividends compound dramatically over decades. The calculator pulls dividend history alongside price data so total return reflects what actually happened to a buy-and-hold investor.

AlphaVantage provides free, reliable historical price + dividend data via API. The calculator caches responses for 60 seconds and falls back gracefully if the API rate-limits. For tax-grade reporting, always cross-check against your broker's transaction history (the calculator shows market-quoted prices, not your actual fill prices).

No — and SEC disclaimers exist for this reason. Past performance reflects history; future returns depend on company fundamentals, valuation at purchase, market conditions, and macro factors. The calculator is best used to understand what HAPPENED, not to project what WILL happen. Use SIP and Compound Interest calculators for forward planning.

Long-term S&P 500 averages ~10% nominal (~7% real after inflation). Individual stocks can do dramatically better or worse. Beating the index requires either luck or genuine edge; most professional fund managers underperform after fees. For DIY investors, matching the index via low-cost ETFs is the realistic baseline.