S&P 500 Return Calculator

Editor: Preliminary April Data (Apr 8 Close) Now Added!

Note: This calculator works for any two datesPlease click here for a calculator which summarizes 1, 5, 10, 20, and 40 year trailing returns for the S&P 500.

Below is a calculator with a benefit not seen on any other calculators I’ve seen online – one which includes dividend reinvestment.  It uses data from Robert Shiller, available here.  For a stock market calculator which lets you enter any two individual days (not months), try our Wilshire 5000 Reinvestment Calculator,

If you like calculators like this one, please see our Treasury Return Calculator, Gold Return Calculator, and Daily Inflation Calculator – they allow you to pick any days where data is available.

The S&P 500 Dividends Reinvested Price Calculator (With Inflation Adjustment)

One issue you run into a lot when you are discussing optimal savings strategies is the inability of people discussing their returns versus the S&P 500 to produce a fair comparison. They will say, for example, that the S&P 500 index was at the same level as it was at some time in the past – so therefore investing in the index was a waste of time.  Here’s the key to this 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

Professor Shiller lists his methodology on his site – all values internal to this tool use the values he provided.  One thing to note is that the month’s ‘Price’ isn’t the price on a particular day, but an average of closing prices based on a year’s quarter’s data.  It’s best to look at it like “what did the average investor who invested randomly during the beginning month and sold randomly during the ending month do?”.

To calculate the ‘dividend reinvested’ price index, I take the dividend yield reported in any month of Shiller’s data and divide by 12 to get an approximate count of dividends paid out in the month. Using that number, I calculate how many ‘shares’ of the S&P 500 index I can buy, and run a cumulative count from 1876 to 2012. Is this completely fair? No, but it would be nigh impossible to go back and calculate exact S&P 500 payout dates and figure out what the index was trading at on that date. Deal with it.

Also, transaction fees and management costs aren’t included, which would come out of a ‘real’ investor’s return.

Implications

Does it mean a lot to include reinvested dividends? Well, yes. Consider the following – in July 1999 Shiller’s data has the S&P 500 at 1380.99. In April 2012? 1386.43. If you only used the price return of the S&P 500 you’d appear to have made a .394% gain, when, dividends reinvested, it was more like a 26.253%% gain. It seems shabby, but the effect is much more pronounced over longer periods of time. Consider from January 1950 until April 2012 the return was 8,182.464% for the index price and a whopping 66226.545% for the dividends reinvested index. In short? Since 1950, roughly 89% of your gains would have come from reinvesting your dividends. Still think it’s shabby?

Thank Yous

To Robert Shiller, of course, for posting his data publicly.
To Ken Faulkenberry at Arbor Investment Planner for finding an error with the dividend calculation in an earlier version of the tool – yes, everything was off by a factor of 12 with dividends. Sorry folks, and thanks Ken for pointing it out!

Is this a useful tool? Anything else you’d like to see added?

Tweet about this on Twitter28Share on Facebook44Share on Google+1Share on Reddit0Share on StumbleUpon2Email this to someone

Comments

  1. says

    Neat stuff PK!  I think that’s a really neat tool.  I haven’t looked at CPI data much but I’m sure a CPI weighted calculator would be really handy too.  Nice work!

    • says

      Thanks! Due to popular demand (2/2 comments), I went back and added the CPI adjustment this morning. Hope it’s useful for comparing strategies, or at least settling arguments!

  2. says

    It’s a hugely important tool, PK.

    I of course agree 100 percent that dividends need to be included. The numbers aren’t accurate if you don’t include dividends.

    Are the numbers here inflation-adjusted? I believe that Shiller uses inflation-adjusted numbers. So I am assuming they are. But I didn’t see language specifically saying that (it’s possible that I missed it), so I am not entirely sure.

    Rob

    • says

      He does, and he doesn’t, but now I’ve got both. I’ve added a checkbox to take inflation into consideration.

  3. freeby50 says

    Nice work.    Thanks for making this.

    I’ve been using the data on Yahoo finance for an S&P500 index and then simply doing the math myself.  I believe their info adjusts for dividends.   But your tool makes it simple.

    • says

      Not sure on the S&P, but Shiller’s data made it pretty easy. I just made two indices and kicked it out as XML and wrote the script.

      Let me know if you think of any other high value calculators – I want to increase the inventory on the site, haha.

  4. says

    I’ve added a checkbox to take inflation into consideration.
    That’s super, PK.

    I have a section at the home page of my blog titled “Links That Matter.” As soon as I post this comment, I will go over there and add your calculator to the other good stuff there.

    Hope it’s useful for comparing strategies, or at least settling arguments!

    My experience tells me that it will start two new arguments for every one that it settles. And that that’s a good thing!

    Rob

  5. says

    I think it’s ridiculous so many investors compare their returns with the S&P 500 in the first place. Unless your portfolio has a beta of 1 (or close to it) there’s no point anyway.

    Sadly, I saw this in many financial advisory offices. They want to compare their results to the S&P 500 when it suits them then remind people that “we aren’t competing with the S&P” when it doesn’t.

    Thinking out loud and off the cuff:  I’m wondering if indexing is creating some big problems for us, as a society. It seems like it encourages the status quo. That’s not a wholly developed thought, so don’t hold it against me when we prove it wrong in 15 minutes.

    • says

      Heh, I won’t hold anything against you Joe!

      I just like the idea of a benchmark in that it’s important to know “what if you hadn’t tried to do anything special?”. If I am beating the ‘market’ I know that my time (the time I spend is more than I would to just sink it into a market fund) is worthwhile.

  6. says

    Leave it to a programmer to try to break it…..December 1997 through December (yeah I know we aren’t there yet) 2012 returned negative 100% in all fields….maybe an entry error would help prevent idiots like me from entering unintelligent data!

    • says

      Looks like we’re in for a massive market fall?

      Sorry for the laziness. My day job wouldn’t let me get away with it; I added some boundary conditions and thanks for checking my work!

  7. Kristin says

    This is a really great tool. Thanks for making it available. I am getting a bad data result. Running a search for October 2009 through December 2009 is getting me “infinity.000% results across all fields. I’ll try coming back to it a different way and see if the result changes.

  8. Priyesh says

    Thank you so much for the tool. I use it to compare the returns hedge funds achieve!

    A really useful tool would be to have a listing of funds and hedge funds with their published monthly performance numbers. Users would then be able to select a date range and compare against the S&P 500.

    I don’t think such a tool already exists and believe other commercial sites would link to your website for such information.

  9. says

    I put Jan 2012 start date and Dec 2012 end date then hit calculate. Why would there be a 1.2% delta between “Annualized S&P 500 Return (Dividends Reinvested)” and “S&P 500 Return (Dividends Reinvested)?” What causes the delta? Great tool by the way! Thanks.

    • says

      In this case it is annualizing based on 12 months, and it’s counting the Jan-Dec time-frame is counted as 11 months. The delta is from ‘filling in’ the last month, so to speak.

  10. xxx says

    Great tool. But this calc shows annualized Div reinvested 2012 (jan-dec) as 12.557% whereas S&P shows the 2012 return to be about 16%. Why the difference?

    • says

      A couple reasons – Jan-Dec is only an 11 month period in the tool. You should try Jan-Jan or Dec-Dec for a better read.

      Additionally, Shiller’s numbers are interpolated quarter returns (and interpolated dividends), as opposed to closing numbers o specific numbers. In this case, you should trust S&P – I did the math in this post if you’re interested.

  11. Philip says

    Thanks so much for sharing this tool. Is there any value to showing or adding a calculation for S&P 500 Total Return with Dividends but not reinvested? Philip

    • says

      You’re the first to ask – do you think you could share an example of what you mean? Figuring it out is easy if you mean “Price return + total of all dividends”, you should be able to just do addition on the Shiller numbers.

      • Philip says

        If an investor owned the S&P 500 for 10 years, for example, received dividends but did not reinvest them, it would seem that investor received a return somewhere between or at least different from the price only return and the total return of reinvesting those dividends along the way. I could add the dividends up, but I thought time value and CPI impact might be worth including – but I am probably just out of my depths here. In any case, the tool above is great and will suffice. Thanks.

        • says

          We’d have an issue though – if an investor first invested in the S&P 500 in, say, 1980, and didn’t pull it out until this month, they’d have a good amount of cash from the dividend payments. If we just added them up, we wouldn’t be accounting for the interest rate earned on that cash – whether it was the brokerage’s sweep, or moved to a savings account, or some other scenario.

          I think dividends in cash is a hard treatment for that reason… if only because it’s hard to figure out what happens to the dividends after the fact.

    • says

      Shiller’s dividend numbers don’t represent any day, but are an interpolation of quarterly data. Index prices he updates on a monthly basis, but he used to interpolate from yearly data. You should check out his site for details.

      Short answer? They are ‘average’ for the month, and not tied to any individual day.

      • Ted says

        I have the same question. For example, if I choose November 2007 as a beginning date, am I beginning with November 1, November 30 or something else? I stumbled across you calculator a few weeks ago and very much appreciate having it available. Just trying to better understand what I am seeing.

        • says

          Hi Ted, thanks for being a fan!

          It’s not a specific day, per se, but more of a determination of what an ‘average’ investor would return. Specifically, from Shiller, “Monthly dividend and earnings data are computed from the S&P
          four-quarter totals for the quarter since 1926, with linear interpolation to monthly
          figures.”

          So, if you pick November 2007 to November 2008 you’re looking at the return of an average investor who was in the market for a year from 2007 to 2008, but not ‘an investor who invested on November 1 and sold on November 30′ or similar.

          I’ve considered doing a total return calculator based on the S&P Total Return index, which allows you to directly compare 2 days. The issue? The TR data only goes back to 2009.

          • Ted says

            Maybe a better way to ask the question is to ask what it means to choose a particular month as the beginning month. Does the calculator include the data for the month chosen, or does it begin with the data for the following month? Or, does the calculation create a beginning point in some other fashion?

          • says

            If you’re asking my algorithm, basically:

            1) Grab the index price for the beginning month (from the Shiller data)
            2) Figure out how many new shares are bought based on taking his dividend data and dividing by 12 (it’s trailing data).
            3) In the next month, use the new number of shares owned to calculate the dividend
            4) Buy ‘new shares’ with the dividend
            5) Rinse, repeat, until the final month.

            I think the magic is in the Shiller calculations – note the S&P “500″ didn’t exist before ’57, so before that he grafts older S&P indices onto the data.

          • Ted says

            Recently, I’ve been trying to measure the performance of our investments since November 1, 2007, the high point in our financial lives prior to the meltdown.

            Unfortunately, in my wife’s view anyway, I’ve been obsessed with tracking our investments for about 25 years now, calculating the value of our assets on an almost daily basis for many years now. Before mutual fund prices became easily available on the internet, I used to call the fund companies automated response numbers to get NAVs for our funds. I know; I’m a nut case, so take my questions for what they are — the wonderings of someone who really ought to get a life!

            From reading other comments and responses and Shiller’s explanation of his data, I understand that the tool is not precise and is based on averages and interpolations. Nonetheless, the tool is the best thing I have stumbled upon so far, and I’m trying to understand how it works.

          • Ted says

            Sorry, ran out of characters.

            Anyway, it sounds like when I plug in Nov. 2007 as the beginning point and Jan. 2013 as the end point, the result — in layman’s terms — is really from something like mid Nov. 2007 to something like mid Jan. 2013. Is that at least approximately correct?

            Thanks again for making this available.

          • says

            That’s one way to think about it, and probably best for what you described – from ‘Sometime in November’ 2007 until ‘Sometime in January’ 2013 (In early March we’ll have the February numbers). It’s impossible to get it to the day by day precision you were looking for, but it should get you in the right ballpark.

            My apologies to your wife, but take a look at the S&P 500 Total Return index. It should let you go day by day with your checks (same assumptions – no taxes or transaction fees), but I’m pretty sure it only goes back to 2009. You could use this tool to get benchmark returns up until when that index begins, then move to the day to day index for more recent market returns.

  12. Ted says

    A link and a question. I stumbled across this source of daily values for the S&P Total Return Index about a month ago: http://www.dailyfinance.com/quote/snpindex/sp-500-total-return-index/%5Esp5tri/historical-prices

    I have no idea how accurate it is. It does provide specific date values for the index for several years. I am only interested in the last six or so, but it appears to go back at least 10 years, if not much further.
    Any knowledge of where the data comes from or how accurate it is?

    • says

      Looks like the S&P 500 Total Return Index… I may have mentioned it (it’s published by S&P). They don’t have an API for me to pull, but since you are using it for personal reasons you can use those numbers (in a spreadsheet or something) then adjust for inflation by using my inflation calculator:

      http://dqydj.net/an-inflation-calculator-with-data-for-any-day-since-1913/

      As far as I know it should be accurate – I used SPTR numbers for my articles on the 2012 total return and for the ‘True Top’ S&P 500 article, heh.

Trackbacks

  1. [...] En eso tiene razón. Hay que descontar de inversión y hay que tener en cuenta varias fechas de inversión para evitar que por un año malo, una cohorte de pensionistas pierda sus ahorros. Por ello, emplearé calculadoras de retornos del SP500 que descuentan inflación, y consideraré un periodo de inversión de 30 años. En general se obtienen (reinvirtiendo dividendos y descontando inflación)en todos los periodos de 30 años retornos superiores al 5.3% anual. La media histórica efectivamente ronda el 7% y desde 1971, del  6.984%. Esto no es del todo realista: un pensionista invertirá año a año, esté la bolsa alta o baja y habría que tener eso en cuenta. Fuente: http://dqydj.net/sp-500-return-calculator/ [...]

  2. [...] Between 2002 and 2012, hedge funds didn’t even beat inflation, underperforming the S&P 500 in 9 out of the 10 years. Historically, hedge funds were supposed to perform better in down years (hence, the term hedge), but recent performance has shown that shortcoming. That’s BEFORE you tack on fees. After fees, in the previous decade, hedge funds had a 17% return. The annualized S&P 500 returns, including dividends, during the same period were 54.3%. [...]

  3. […] If you are in the camp that says this last five years has been an anomaly, history may beg to differ. Over the last 50 years we have experienced wars, assassinations, currency crises, banking crises, terrorist attacks, recessions, SARs, mad cow disease, military engagements, tax hikes, Fed rate hikes, and yes, even political gridlock. As the chart below shows, the stock market is volatile over the short-run, but quite resilient and lucrative over the long-run (+6,863% over 49 years). In fact, from January 1960 to October 2013 the S&P 500 index has catapulted +14,658%, including reinvested dividends (Source: DQYDJ.net). […]

Leave a Reply

Your email address will not be published. Required fields are marked *