It is a
different measure of volatility, just as the VIX formula is. It is not necessarily "better". That must be determined by a peer review.
To answer your question, put the following formula into J2522 formatted as Percentage, and copy it up through J501:
where we also have the following formulas:
K2522: =SUMPRODUCT(ROW($D$2023:$D$2522)-ROW($D$2022))
L2522: =SQRT(2)
M2522: =SQRT(60*24*365/510)
You can put them anywhere, changing the SUMPRODUCT formula appropriately.
Obviously, I simplified the original formula algebraically.
I also made an important change so the result is comparable to the standard definition of volatility; that is, a percentage like the values in your column I.
In contrast, the original formula scales (multiplies) the percentage by 100, perhaps to be comparable to the VIX index. For example, 12.34% becomes 12.34.
I can explain the derivation of the Excel formula in detail, if you wish.
Habermuth attributes the formula to Reinhold Fend and Christian Luible, “Historische Volatilität: Annualisierte Standardabweichung versus neue Berechnungsmethode”, Vereinigung Technischer Analysten Deutschlands e. V., January 2009.
But without seeing the Fend and Luible paper, preferably in English

, I can only guess about a key detail that is not explained. To wit....
The formula uses the subscript t-i+1. What is "t"? Presumably "t" is the same as (and should be) "T". That is, it is the time index for which we are calculating volatility. And presumably t>=2*n is true; otherwise, t-i+1 might be a negative subscript. I believe t=2*n. That is how I used it in the Excel formula above.
In summary, the Fend-Luible formula seems to calculate the annualized trailing weighted moving average (WMA; a.k.a "sum of the digits"[*] weighted average) of the percentage difference between the daily low price and daily average price over 2*n days.
Well, the WMA divided by SQRT(2). I have no explanation for that. (Well, a guess; but I don't like it.)
[*] "Sum of the digits" is a misnomer, IMHO. It should be "sum of the numbers".
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