IV Rank & IV Percentile Calculator
See whether today's implied volatility is high or low compared with the stock's own history. Enter the current IV and its past range, and optionally paste past readings for a true percentile.
Free and private: runs entirely in your browser, nothing is uploaded.
How to use
- Find the stock's current implied volatility on your broker's quote or option chain.
- Enter the lowest and highest IV over the past year (many platforms show this).
- Optionally paste past daily or weekly IV readings to calculate IV percentile.
Formulas explained
IV rank only uses the high and low, so one extreme spike can distort it. IV percentile uses every reading, which shows how often IV has actually been lower. When they disagree, percentile is usually the more representative number.
Worked example Hypothetical
Current IV 32%, 52-week range 18%–58%. IV rank = (32 − 18) ÷ (58 − 18) = 35. That looks low-ish, but in the 30 sample readings above, 23 were below 32%, so IV percentile is about 77%. The single 58% spike made the rank look lower than IV really is, relative to normal.
IV rank explained for beginners
What this tool does
Each stock has its own normal level of implied volatility. A 40% IV is high for a utility stock and low for a small biotech. IV rank and percentile put today's IV in the context of that stock's own past, so you can tell if its options are relatively expensive or cheap.
How traders use it
Option sellers (covered calls, credit spreads, iron condors) often prefer higher IV rank because premiums are richer. Buyers (long calls, calendar spreads) may prefer lower readings. High IV is not a free edge: it usually exists because the market expects bigger moves.
Common mistakes
- Comparing IV across different stocks instead of within one stock's history.
- Ignoring upcoming earnings, which push IV up temporarily.
- Treating IV rank as a timing signal. IV can stay high or low for a long time.
- Mixing sources: different platforms compute IV and its history differently.
Learn more in what is implied volatility.
FAQ
What is a high IV rank?
Many traders call above 50 high and below 20 low, but these are conventions, not rules.
Why do IV rank and percentile differ?
Rank uses only the high and low, so one spike skews it. Percentile counts every reading.
Related tools
Not financial advice
This tool is for educational and informational purposes only. It is not financial, investment, tax, or legal advice, and it is not a recommendation to buy or sell any security or to use any strategy. All examples use hypothetical numbers. Options involve risk and are not suitable for everyone. Do your own research and consider talking to a licensed professional before trading.
Learn the strategy
Bull Put Credit Spread · Covered Call · How to Read an Options Chain