What Is Implied Volatility Rank (IV Rank)?
Implied Volatility Rank (IV Rank or IVR) is a metric that measures the current implied volatility of a stock relative to its own historical range over the past 52 weeks. It answers a simple but critical question: is the current implied volatility high or low compared to where it has been over the past year? IV Rank ranges from 0 to 100, where 0 means IV is at its 52-week low and 100 means it is at its 52-week high.
IV Rank was popularized by tastytrade and has become one of the most widely used indicators in options trading. It allows traders to compare volatility levels across different stocks and time periods on a normalized scale. A stock with 40% IV might be relatively cheap if its IV ranged from 30% to 80% over the past year (IVR = 20%), but relatively expensive if its range was 25% to 45% (IVR = 75%).
IV Rank compares the current IV to the highest and lowest IV readings over the past year. IV Percentile measures what percentage of days in the past year had a lower IV than today. Both are useful, but IV Rank is more commonly referenced by options traders for strategy selection.
How to Calculate IV Rank
- 1IV Range = 65% - 20% = 45 percentage points
- 2Current IV above low = 35% - 20% = 15 percentage points
- 3IV Rank = (15 / 45) × 100 = 33.3%
- 4IV-HV Spread = 35% - 30% = +5% (IV is above HV, options are slightly overpriced)
- 5Assessment: IV Rank of 33.3% is in the low-to-moderate range
How IV Rank Guides Strategy Selection
| IV Rank Range | IV Level | Preferred Strategies | Rationale |
|---|---|---|---|
| 0-25% | Low | Long calls, long puts, debit spreads, calendars | Options are cheap; buying premium is favorable |
| 25-50% | Below Average | Debit spreads, diagonal spreads | Moderate environment; slight edge to buyers |
| 50-75% | Above Average | Credit spreads, iron condors, short strangles | Options are getting expensive; selling has an edge |
| 75-100% | High | Short strangles, iron condors, short straddles | Options are expensive; selling premium is highly favorable |
IV Rank vs. Historical Volatility Spread
The IV-HV spread compares implied volatility to actual historical (realized) volatility. When IV is significantly higher than HV, it suggests options are overpriced relative to the stock's actual movement. This creates an edge for option sellers. When IV is below HV, options may be underpriced, favoring option buyers.
Combining IV Rank with the IV-HV spread provides a more complete picture. A high IV Rank with a wide positive IV-HV spread is the strongest signal for selling options. A low IV Rank with a negative IV-HV spread strongly favors buying options. When the signals conflict, traders should reduce position size or seek more information.
Common Uses of IV Rank in Trading
- Screening for option selling opportunities: Filter stocks with IV Rank above 50% for credit spreads and iron condors
- Timing covered call entries: Sell covered calls when IV Rank is elevated to collect higher premiums
- Avoiding IV crush: Do not buy options before earnings when IV Rank is near 100%
- Cross-stock comparison: Compare opportunity across different stocks by normalizing volatility with IV Rank
- Position sizing: Use higher IV Rank as a signal to increase allocation to option-selling strategies
- Adjusting trade management: Set tighter profit targets when IV Rank is extreme in either direction
Limitations of IV Rank
IV Rank has several limitations traders should understand. First, it is heavily influenced by outliers. A single spike in IV (such as during a market crash) can keep the IV Rank compressed near 0 for months afterward because the 52-week high is so elevated. Second, IV Rank does not account for the direction of IV trends. An IV Rank of 50% during a rising trend has different implications than during a falling trend.
After major market events (like a sharp correction), the 52-week IV high can be extremely elevated, causing IV Rank to read near 0 even when current IV is above normal. Always check the absolute IV level alongside IV Rank for a complete picture.