IV Rank measures where the current implied volatility sits relative to its range over the past year. A rank of 80% means IV is in the top 20% of its annual range — ideal for selling premium.

Where does the data come from?

We pull options data from major exchanges via institutional-grade data feeds, with quotes updated throughout the trading day.

Can I set custom alerts?

Pro users can set alerts on IV rank thresholds. Premium users get custom rule-based alerts including unusual flow triggers.

Yes! Pro and Premium plans include API access for programmatic data retrieval. See our docs for endpoints and rate limits.

How does billing work?

We offer monthly billing. You can upgrade, downgrade, or cancel at any time. No long-term contracts.

December 30, 2025

IV Rank vs IV Percentile: Which Metric Should You Use?

metrics

implied-volatility

analysis

Options traders frequently use IV Rank and IV Percentile to determine whether implied volatility is relatively high or low for a given stock. Both metrics compare current IV to historical IV over a lookback period, typically one year, but they calculate the comparison differently. Understanding the distinction is essential because using the wrong metric can lead you to misread the volatility environment and enter trades with a skewed risk-reward profile.

IV Rank measures where current IV falls within the 52-week range as a simple percentage. The formula is (Current IV minus 52-week Low IV) divided by (52-week High IV minus 52-week Low IV). If a stock's IV ranged from 20% to 60% over the past year and currently sits at 30%, the IV Rank is 25%. This tells you that current IV is closer to the low end of its annual range. IV Rank is intuitive and easy to calculate, but it has a significant weakness: it is heavily influenced by outliers. A single massive IV spike, such as one caused by a market crash, can compress IV Rank for the rest of the year because the high end of the range is so extreme.

IV Percentile, by contrast, measures the percentage of days over the lookback period during which IV was lower than it is today. If current IV is higher than it was on 80% of the trading days in the past year, the IV Percentile is 80%. This metric is more robust to outliers because it considers the distribution of IV values across the entire period, not just the extremes. A single spike day gets counted as one day among 252, rather than anchoring the entire scale.

In practice, IV Percentile tends to be the more reliable metric for making trading decisions. When IV Percentile is above 50%, it means that IV is higher today than it was on more than half the trading days in the past year, which is a reasonable signal that premium selling strategies have an edge. When it is below 30%, options are relatively cheap, and buying strategies deserve more consideration. Many professional traders use both metrics together, looking for situations where both IV Rank and IV Percentile agree that volatility is elevated before committing to a premium-selling strategy.