Does anyone know the formula for actual volatility for a specific stock. I think it is something like: SqRoot of 52 or 365 or 12 (depending on the length you want). That is then divided into the (Price of the Stock/Standard Deviation (STD)). ex. for daily Citigroup --- 19.1/(44.10/STD) I do not know what the is or where to find it for a specific stocks. I have looked on the WWW but am not seeing it. So I guess the real question is, assuming the formula is correct, is where can I find the STD for specific stocks.