Realized Volatility (6M)

Annualized standard deviation of daily log-returns over the past 180 days — a slow-moving anchor for long-term volatility trend analysis

Property	Value
Category	Market Data
Unit	Dimensionless
Resolution	1d
Assets	BTC
Tier	Basic
API Endpoint	GET /v1/prices
Field	realized_vol_6m

Overview

Realized Volatility (6M) measures Bitcoin's annualized price volatility over a trailing 180-day rolling window — covering half a year of daily returns. This is the slowest-moving member of the short-to-medium realized volatility family and acts as an anchor: it takes weeks of persistent high or low volatility to meaningfully shift it.

At six months, this metric spans across full bull-to-correction or consolidation-to-breakout cycles. It is the closest analog to how long-term institutional risk models evaluate asset volatility, and it bridges the gap between short-term realized vol and the annualized 1Y window.

All values are annualized by multiplying the daily standard deviation by $\sqrt{365}$ for consistency and cross-asset comparability.

Formula

$$\sigma_{6M} = \sqrt{365} \times \sqrt{ \frac{1}{N-1} \sum_{i=1}^{N} \left( r_i - \bar{r} \right)^2 }$$

where:

• $r_i = \ln\!\left(\frac{P_i}{P_{i-1}}\right)$ — daily log-return
• $\bar{r}$ — mean of the $N$ log-returns in the window
• $N = 180$ — rolling window size
• The $\sqrt{365}$ factor annualizes the daily standard deviation
• Result is expressed as a percentage

Interpretation

• Low (< 30%): Extremely rare — half a year of subdued moves. Typically seen only in deep bear accumulation troughs (2015, 2019, 2023).
• Moderate (30–55%): The market has been in a broadly orderly phase for six months. Common in mid-cycle bull markets.
• High (55–80%): Sustained turbulence over half a year. Characteristic of late bull markets where corrections are large even as price grinds higher.
• Extreme (> 80%): Prolonged crisis or exceptional multi-month parabolic phase. Increasingly rare as market cap grows.

The 6M vol is the clearest indicator of "what kind of year it has been so far." Its slow decay means it carries memory of major events for months after they occur. The 1M/6M ratio is a powerful signal: values well above 1 indicate the market is more volatile right now than its recent history; values well below 1 suggest the market has calmed sharply.

Use Cases

• Long-term position sizing: Investors holding BTC for 6+ months typically size based on 6M vol to avoid being stopped out by short-term noise while still respecting the true risk of the asset.
• Institutional risk models: Many institutional risk frameworks (VaR, Expected Shortfall) for crypto use 6M or longer lookbacks to avoid underestimating tail risk from a quiet recent period.
• Vol term structure analysis: The full term structure (1W → 2W → 1M → 3M → 6M → 1Y) on a single chart reveals whether markets are in contango (long-term vol > short-term) or backwardation (short-term stress dominates).
• Cycle-phase identification: 6M vol troughing (< 35%) while price is flat is one of the most historically reliable signals of a pre-breakout accumulation phase in Bitcoin's four-year cycles.

API Usage

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.blocklens.co/v1/prices?start_date=2024-01-01&end_date=2024-12-31&limit=365"

Related Metrics

• Realized Volatility (3M) — Annualized standard deviation of daily log-returns over the past 90 days — tracks medium-term volatility across a full market phase
• Realized Volatility (1Y) — Annualized standard deviation of daily log-returns over a trailing 365-day window — measures how volatile BTC price has been over the past year
• Realized Volatility (1M) — Annualized standard deviation of daily log-returns over the past 30 days — the industry-standard short-term BTC volatility benchmark
• Realized Volatility (1W) — Annualized standard deviation of daily log-returns over the past 7 days — a real-time gauge of short-term BTC price turbulence
• Price — BTC market price
• Price Drawdown from ATH — Percentage decline of Bitcoin price from its all-time high — always 0% or negative, measuring how far price has fallen from its peak