This is a free spreadsheet that downloads free historical stock data from the Yahoo database into the spreadsheet and calculates the historical (or realized) volatility of the selected stock and graphs the result.

Features: This is a spreadsheet based utility that shows you historical or realized volatility of a selected stock. The package downloads free historical data from the Yahoo database. You can download historical data that goes as far back as the data maintained by Yahoo!. You are free to choose your own look-back period of course. Volatility is a concept used by options traders to determine if a hoe much of movement a stock is expected to make in a given period. That would tell you if the option is likely to expire in or out of the money by the expiration date. Historical Volatility tells option traders how rapid price movements have been over a given time frame. The most common method of calculating historical volatility is the Standard Deviation. Implied volatility is the markets view of where volatility will be in the future. To determine an option`s implied volatility, the trader must use a pricing model. We can tell how high/low implied volatility is by comparing the market price of an option to the options theoretical fair value. This is why we need to use an option pricing model - to determine the fair value of an option and hence know if the market price for the option is over/under valued. These will determine how to trade. For getting an analysis you change the stock symbol easily. The utility will download appropriate data and give you the new analysis.

Overall: Nice and easy to use and a very useful program. Best of all it is free. As it appears to be the version 1.0 release, look out for bugs; particularly because a bug can cost you money if you do bad trade.