IV Rank
A normalized measure showing where current implied volatility sits within its historical high-low range.
Explanation
A common formula is: (current IV - lookback low IV) / (lookback high IV - lookback low IV). IV Rank helps contextualize whether options are relatively expensive or cheap in the current regime. It is widely used for selecting premium-selling vs premium-buying environments.
Example
If 1-year IV low is 15, high is 45, and current is 30, IV Rank is 50.