Just wondering if there are any other users of the free option analysis spreadsheet that's out there on the web? It is the only one I've found that can project option prices to a target return and show you which one(s) will reach that target with the smallest change in the price of the stock or index. My biggest question has been: when I project the analysis forward for "x" days, what's the best way to guess at the change in volatility over that time? I've been bracketing it, looking at 3 cases: flat, up 10%, down 10%, to get a handle on sensitivity of the different options, but I would like to come up with a more "rigorous" approach. Any suggestions will be welcome!