S&P 500 total return calculator
Pick any start and end month since January 1871. Returns include dividends reinvested monthly, shown both nominal and inflation-adjusted (CPI-U), computed on Robert Shiller's monthly dataset — the same series used in academic research.
Log scale · 437 months · monthly-average prices, dividends reinvested monthly · Shiller data
Landmark start dates, $10,000 invested
| Invested | Nominal (div. reinvested) | Real (inflation-adj.) | CAGR |
|---|---|---|---|
| Jan 1971 | $3.56M | $431,545 | 11.2% |
| Jan 1990 | $448,510 | $173,996 | 11.0% |
| Jan 2000 (dot-com peak) | $83,834 | $43,091 | 8.4% |
| Mar 2009 (crisis bottom) | $134,849 | $87,344 | 16.3% |
Methodology
Prices are the monthly average of daily closes for the S&P Composite, from Robert Shiller's long-run dataset (Yale). Each month, one-twelfth of the trailing annualized dividend is reinvested at that month's average price — the standard approach for long-run total return series. Real figures deflate by CPI-U. The most recent months use S&P Dow Jones Indices dividend reports and BLS CPI-U actuals interpolated monthly, the same practice Shiller applies to his own recent data. The full input dataset (price, dividend, CPI per month since 1871) is republishable under CC-BY 4.0 with attribution.
Because monthly averages differ from single-day closes, results can differ a few percent from calculators using daily data. Neither is wrong — but only monthly-average data exists back to 1871, which is why academic long-run studies use this series.
Frequently asked questions
What is the total return of the S&P 500 with dividends reinvested?
From January 1871 through June 2026, the S&P Composite's total return (dividends reinvested) has annualized at roughly 9% nominal and about 7% after inflation. Over the modern era: $10,000 invested in January 1990 grew to about $448,510 by June 2026 (11.0%/yr), versus only $219,138 without dividends.
How much difference does dividend reinvestment make?
Roughly 2.2 percentage points per year since 1990 — and more in earlier eras when yields were higher. Compounded over decades that is the majority of the market's wealth creation: since 1871, price-only growth explains a small fraction of the total return; reinvested dividends explain the rest.
What if I invested $10,000 at the March 2009 bottom?
$10,000 invested in March 2009 (the financial-crisis low) grew to about $134,849 by June 2026 with dividends reinvested — roughly 16.3% annualized. The same amount invested at the January 2000 dot-com peak reached only $83,834 (8.4%/yr) — start dates matter enormously over 20-30 year windows.
Why does this calculator use monthly average prices?
It follows Robert Shiller's long-run dataset, which records the monthly average of daily closing prices rather than a single day's close. Averages smooth out day-level noise and allow a consistent series back to 1871, decades before daily data exists. Results can therefore differ by a few percent from a calculator using specific-day closes — both are correct on their own terms.
Is the data inflation-adjusted?
Both figures are shown: nominal (actual dollars) and real (deflated by CPI-U, so the answer is in purchasing power of the end date). For long horizons the real figure is the honest one — $10,000 invested in January 1971 became $3.56M nominal, but that equals only $431,545 in end-date purchasing power.
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Sources: Robert Shiller, Yale (long-run monthly data); S&P Dow Jones Indices (recent dividends); BLS CPI-U. Snowballr provides financial education, not investment advice.