Offer your thoughts or opinion on the input financial query or topic using your financial background.

A calculator that takes into account portfolio rebalancing?
R has really good package that lets you calculate the return of rebalanced portfolios. The package is called: PerformanceAnalytics (see: http://www.inside-r.org/packages/cran/PerformanceAnalytics/docs/Return.portfolio). I quickly wrote a small script for you that lets you do exactly what you want.  Code: By default the portfolio is rebalanced to an equally weighted portfolio. It is also possible to rebalance your portfolio using custom weights. See the documentation on how to do this.  In order for this code to work you need to have your data already in return terms. You can do this easily in Excel. Make sure your data in excel looks like this: Than export your data to a CSV file. Note: before you run the code make sure you have installed the package PerformanceAnalytics. You can do this as follows:  Let me know if you have any questions regarding the above.