I am just starting to invest. I would like to find a calculator to which I could enter, say, a monthly amount - perhaps $100 - and put it into different classes of funds over arbitrary periods (say from March of 2011 to February of 2013).

If it could calculate loads and fees, that would be icing on the cake.

The idea is, I remember certain key periods and what the economy was doing. A tool like this would help a new person like me make informed decisions for the future. Appreciate your help.

  • It is very hard to find a tool that backtests time weighted or money weighted returns with monthly Dollar Cost Averaging. Most tools only allow one-time allocation with a set of funds and monthly rebalancing. If you were to contribute $100 monthly to a cash fund say SHV, all you get is a upward straight line. – base64 Aug 8 '15 at 7:25
  • This is a link to MAthematica SE. [forecast-future-stock][1] [1]: mathematica.stackexchange.com/questions/25733/… – Bob Brooks Aug 10 '15 at 15:35

The professional financial advisors do have tools which will take a general description of a portfolio and run monte-carlo simulations based on the stock market's historical behavior. After about 100 simulation passes they can give a statistical statement about the probable returns, the risk involved in that strategy, and their confidence in these numbers.

Note that they do not just use the historical data or individual stocks. There's no way to guarantee that the same historical accidents would have occurred that made one company more successful than another, or that they will again. "Past performance is no guarantee of future results"... but general trends and patterns can be roughly modelled.

Which makes that a good fit for those of us buying index funds, less good for those who want to play at a greater level of detail in the hope of doing better. But that's sorta the point; to beat market rate of return with the same kind of statistical confidence takes a lot more work.

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  • I hadn't heard the term "Monte Carlo" in a while :) Thanks for helping me getting (back) into investing. I was wanting something more simple, e.g., "What would have been my ROI or net increase/loss if I had been in SOPFX (Strong's Opportunity Fund) from January 2003 to August 2004 with accrued contributions of 100, 200, 300, 400, ..". It would need to take into account the value of SOPFX on Jan 1st, Feb 1st, March 1st, etc.. – Oliver Williams Aug 9 '15 at 12:52
  • Ideally, it would also look at the historical load or cost on the fund for the answer to be more accurate over time. keshlam, based on the response to this post so far, there may not be a tool that does just that :) – Oliver Williams Aug 9 '15 at 12:54

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