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Results use historical S&P 500 calendar-year total returns and are hypothetical: they ignore fees, taxes and inflation, and assume you kept investing every month. Past performance does not guarantee future results; investing can lose money. Educational content only. Not financial advice. See our Disclaimer.
Quick answer: $100 a month in an S&P 500 index fund from 1996 through 2025 would have grown to about $232,000 from $36,000 invested, using real yearly total returns with dividends reinvested, crashes included. Past returns do not guarantee future results.
What this S&P 500 return calculator uses
Real calendar-year total returns of the S&P 500 (price change plus reinvested dividends) from 1970 to 2025 — not a flat average. That means your result includes the 2000–2002 crash, 2008 (−37%), 2022 (−18%) and the recoveries after each. Each year’s return is spread evenly across its twelve months.
What it does not include
Fund fees (an index fund today costs around 0.03% a year), taxes, and inflation. It also assumes you kept buying through the crashes, which is the whole trick — and the hardest part.
Three things to try
- Start in January 2000, the worst possible moment of the last 30 years, and see where you end up anyway.
- Compare 1995–2024 with 1985–2014: same 30 years, different path, similar lesson.
- Change the monthly amount — the result scales exactly with it.
Watch: how to invest in the S&P 500
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What would $100 a month in the S&P 500 be worth after 30 years?
Using the real 1996–2025 returns, about $232,000 from $36,000 invested; 1990–2019 gives about $190,000. The start year matters a lot. Run the calculator for any window.
What is the average annual return of the S&P 500?
About 10% a year with dividends reinvested since the 1920s, and about 11% over 1970–2025 — but with individual years ranging from −37% (2008) to +37% (1995).
Where do the numbers come from?
S&P 500 total return by calendar year as published by S&P Dow Jones Indices and reproduced by Slickcharts and others. 2026 is excluded because the year is not finished.
Does this S&P 500 calculator include dividends?
Yes. It uses calendar-year total returns, meaning price change plus reinvested dividends. It does not subtract fund fees, taxes or inflation.
What would $1,000 a month in the S&P 500 be worth after 30 years?
The result scales exactly with the amount, so 10 times the $100 result: about $2.3 million for 1996–2025. A different 30-year window gives a different answer; run the calculator for any start year.