Volatility Percentile/rank

What is Volatility Percentile/Rank?

Volatility percentile/rank normalizes a volatility measure against its own history. Take any gauge, such as ATR or close-to-close historical volatility, and ask where the current reading sits within a lookback window. The percentile version reports the share of past readings at or below today's; the rank version scales today's reading between the window's minimum and maximum. Both compress raw volatility onto a 0 to 100 scale that means the same thing on any symbol and any timeframe.

The construction is borrowed from the options world, where IV rank and IV percentile normalize implied volatility over the trailing year, and it is applied to realized measures for the same reason: a 2% daily range is sleepy for one instrument and violent for another, so absolute numbers do not travel. Low percentiles flag compression, which often precedes expansion but does not schedule it; high percentiles flag stress that has tended historically to subside, though it can persist.

How traders use it

• As a strategy gate: breakout systems often require a low volatility percentile (compression) before arming entries, while mean-reversion systems may trade only when the percentile is elevated, matching each edge to the regime it was built for.
• As a screener: because the scale is normalized, percentiles can be compared across an entire watchlist to surface the most compressed or most stressed markets at a glance.
• As a sizing input: volatility-targeted sizing and stop-width rules read normalized volatility to scale positions down when a market runs hot and up when it is quiet.