The volatility of Bitcoin prices is one of the strongest headwinds the currency faces. Unfortunately, until my quantitative analysis last month, most of the discussion surrounding Bitcoin volatility so far has been anecdotal. I want to make it easier for people to move beyond anecdotes, so I have created a Bitcoin volatility index at btcvol.info, which I’m hoping can become or inspire a standard metric that people can agree on.

The volatility index at btcvol.info is based on daily closing prices for Bitcoin as reported by CoinDesk. I calculate the difference in daily log prices for each day in the dataset, and then calculate the sample standard deviation of those daily returns for the preceding 30 days. The result is an estimate of how spread out daily price fluctuations are—volatility.

The site also includes a basic API, so feel free to integrate this volatility measure into your site or use it for data analysis.

I of course hope that Bitcoin volatility becomes much lower over time. I expect both the maturing of the ecosystem as well as the introduction of a Bitcoin derivatives market will cause volatility to decrease. Having one or more volatility metrics will help us determine whether these or other factors make a difference.

You can support btcvol.info by spreading the word or of course by donating via Bitcoin to the address at the bottom of the site.