S&P 500: $100 in 2021 → $122.21 in 2021


Stock market returns between 2021 and 2021

If you invested $100 in the S&P 500 at the beginning of 2021, you would have about $122.21 at the end of 2021, assuming you reinvested all dividends. This is a return on investment of 22.21%, or 22.21% per year.

This lump-sum investment beats inflation during this period for an inflation-adjusted return of about 22.21% cumulatively, or 22.21% per year.

If you used dollar-cost averaging (monthly) instead of a lump-sum investment, you'd have $0.00.

The graph below shows the performance of $100 over time if invested in an S&P 500 index fund. The returns assume that all dividends are automatically reinvested.

This chart shows the rate of gains and loss by month, including dividends:

Adjusting stock market return for inflation

The nominal return on investment of $100 is $22.21, or 22.21%. This means by 2021 you would have $122.21 in your pocket.

However, it's important to take into account the effect of inflation when considering an investment and especially a long-term investment. You can convert S&P returns to their real (inflation-adjusted) value using an inflation calculation based on the U.S. Bureau of Labor Statistics Consumer Price Index (CPI).

In the case of the returns described above, the CPI in 2021 was 270.970 and the CPI in 2021 was 270.970.

The ratio between these CPIs describes how relative buying power of a dollar has changed over 0 year.

Adjusted for inflation, the $122.21 nominal end value of the original $100 investment would have a real return of roughly $22.21 in 2021 dollars. This means the inflation-adjusted return is 22.21% as opposed to the original 22.21%.

For more information on inflation, see our U.S. inflation calculator for 2021.

Full monthly data

The table below shows the full dataset pertaining to a $100 investment, including gains and losses over the 12-month period between 2021 and 2021.

Note that data shown is the monthly average closing price. Returns include dividends.

YearMonthReturn (%)Amount ($)CPI
Click to show -6 more rows

Remember, returns are based on the average closing price across the entire month. Some losses are offset by dividend returns.

Dollar-cost averaging

Dollar-cost averaging is an alternative to investing the full lump-sum of $100.00 up-front. Instead, the capital is invested over a period of time.

Consider a strategy in which $100.00 was invested in the S&P 500 over a period of no more than 24 months beginning in 2021. This would result in a final amount of $0.00, including dividend reinvestments. In this particular case, dollar-cost average returns are less than the returns of a lump-sum investment (which ends with $122.21).

YearMonthContribution ($)Amount ($)
Click to show -6 more rows

Data Sources

The information on this page is derived from Robert Shiller's book, Irrational Exuberance and the accompanying dataset, as well as the U.S. Bureau of Labor Statistics' monthly CPI logs.

Note that S&P index value for the current quarter is based on a moving average of closing prices, per Robert Shiller's methodology. The inflation data used is based on annual CPI averages.

Ian Webster

About the author

Ian Webster is an engineer and data expert based in San Mateo, California. He has worked for Google, NASA, and consulted for governments around the world on data pipelines and data analysis. Disappointed by the lack of clear resources on the impacts of inflation on economic indicators, Ian believes this website serves as a valuable public tool. Ian earned his degree in Computer Science from Dartmouth College.

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S&P 500 from 2021 to 2021
Start Value
Average monthly close
End Value
Average monthly close
Change in price+0.00%
+0.00% / yr
Change incl. dividends+22.21%
+22.21% / yr
Change incl. dividends, inflation-adjusted+22.21%
+22.21% / yr
Final amount, nominal
($100 base)
Final amount, inflation-adjusted
($100 base)