Below is a *S&P 500 return calculator with dividend reinvestment*. It has Consumer Price Index (CPI) data integrated, so it can estimate total investment returns before taxes. It shows the price return of the index along with the estimated effect of reinvested dividends.

## S&P 500 calculator: nominal and inflation-adjusted

*Through 8/15/24 Close. For last year, see the 2023 S&P 500 return.*

Here are the fields you'll see after using this S&P 500 return calculator:

**S&P 500 Index Return**- The total price return of the S&P 500 Index. So if it is at 1000 on the start and end date, this will be 0.**S&P 500 Index Annualized Return**- The total price return of the S&P 500 index (as above), annualized. This number basically gives your 'return per year' if your time period was compressed or expanded to a 12 month timeframe.**S&P 500 Dividends Reinvested Index Return**- The total price return of the S&P 500 if you had reinvested all of your dividends.**S&P 500 Dividends Reinvested Index Annualized Return -**The total price return of the S&P 500 if you reinvested dividends**.**Again, it will annualize the return given above.**Inflation Adjusted (CPI)? -**Whether the calculation you did is using CPI adjusted values provided by Shiller, or showing return before inflation. Hit the checkbox above the buttons to turn on or off the inflation adjustment.

## Methodology of the S&P 500 Return Calculator

Professor Shiller lists his methodology on his site - all values internal to this tool use the values he provided (outside of the most recent month).

### How do monthly S&P 500 prices work?

The month's 'Price' isn't the price on a particular day, but an average of closing prices. It answers **"what did the average investor who invested randomly during the beginning month and sold randomly during the ending month do?"**.

Let me say that again in a different way: other than the most recent month, which is tied to one closing price (and listed in the editor note at the top of the page), the **month DOES NOT correspond to an individual day**. It's a guess at an average investor's price basis (or sale price) if they bought (or sold) "at some point" in the month.

Also, important (since it comes up often in the comments): because it ** isn't an individual date**, that means when you're trying to compute yearly returns, you need to be careful to pick twelve months - so, if you were interested in the annual return of 2013, you would pick Jan-2013 to Jan-2014 or Dec-2012 or Dec-2013 to get roughly 12 months.

If you want exact dates, try our mutual fund return calculator or ETF return calculator.

### How do dividend prices work?

To calculate the 'dividend reinvested' price index:

- Take the trailing twelve month dividend yield reported in any month of Shiller's data.
- Divide by 12 to get an approximate count of dividends paid out in a month.
- Calculate how many 'shares' of the S&P 500 index you can buy.
- Run a cumulative count from your start to your chosen end date.

This will, of course, not match the results on an individual investor. It's impossible to go back and calculate exact S&P 500 payout dates for each fund in each brokerage, and figure out what the index was trading at on that date.

### Other Calculators and Other Ways to See S&P 500 Historical Return Data

We *also* present this data from the perspective of average return over various time periods.

- A Treasury Return Calculator using the same data can be found at that link.
- We also have a similar calculator based on the Dow Jones Industrial Average.
- An ETF Return Calculator, which may better approximate how individual investors performed.
- Finally, try our individual stock dividend reinvestment calculator.

*Also: Our S&P 500 Periodic Reinvestment calculator can model fees, taxes, etc. The S&P 500 History Calculator lets you compare time periods. Also see our CAPE/Shiller PE calculator for valuation.** For all our calculators, go to this page.*

*Also: Our S&P 500 Periodic Reinvestment calculator can model fees, taxes, etc. The S&P 500 History Calculator lets you compare time periods. Also see our CAPE/Shiller PE calculator for valuation.*