I've been asked to share my rebalancing calculator, so I thought it'd be best to put it in a thread.

This is what it looks like fresh:

Put in the current values for your portfolio, and it will tell you if you need to rebalance:

You can also include contributions, and it will calculate a "Contributions Only" column, if you prefer Lazy Rebalancing (rebalancing with contributions only). It will include the contributions in the main rebalance calculation:

Finally, if you input a negative number for "Amount to Invest" it will tell you which assets to withdrawal, while keeping you as close as possible to your target allocation:

If you don't have Excel, it works great in LibreOffice -

https://www.libreoffice.orgThe calculator is based on Vanguard's

Best Practices for portfolio rebalancing. Rebalancing is easy, and you're just fine doing it once a year. This is what Vanguard says about rebalancing:

"Our findings indicate that there is no optimal frequency or threshold when selecting a rebalancing strategy. This paper demonstrates that the risk-adjusted returns are not meaningfully different whether a portfolio is rebalanced monthly, quarterly, or annually". As a result, they recommend rebalancing annually, with a 5% threshold. They call this the Time-and-threshold rebalancing strategy, and describe it as:

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**Strategy #3: ‘Time-and-threshold’**"The final strategy discussed here, “time-and- threshold,” calls for rebalancing the portfolio on a scheduled basis (e.g., monthly, quarterly, or annually), but only if the portfolio’s asset allocation has drifted from its target asset allocation by a predetermined minimum rebalancing threshold such as 1%, 5%, or 10%. If, as of the scheduled rebalancing date, the portfolio’s deviation from the target asset allocation is less than the predetermined threshold,

**the portfolio will not be rebalanced**. Likewise, if the portfolio’s asset allocation drifts by the minimum threshold or more at any intermediate time interval,

**the portfolio will not be rebalanced at that time**."

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So they recommend looking at the portfolio once a year, and rebalancing only if it deviates by 5% from your target. If it doesn't deviate,

**don't rebalance**. They did the math using market returns from 1926-2009, and charted it out for us:

Their portfolio from 1926 to 2009 only had to rebalance 28 times, or about one out of every 3 years. Don't worry about rebalancing, that's the easy part. The hard part is keeping your costs down, and staying the course :) Let me know if anything's broken!

Edit: Just realized you can't see the link if you aren't logged in. Login to see the file.

Edit 2: New version which auto updates balances based on market price, requires LibreOffice 4.4+ and this extension:

http://extensions.libreoffice.org/extension-center/smf-extension