IV Rank Explained: How to Know When Options Are Cheap or Expensive
IV Rank tells you whether implied volatility is historically high or low — and it's one of the most useful filters for deciding when to buy or sell options.
Implied volatility (IV) tells you how much the market expects a stock to move. But high or low compared to what? That's where IV Rank comes in — and it's one of the most useful tools in an options trader's toolkit.
What is implied volatility?
Before IV Rank, a quick primer. Implied volatility is the market's forward-looking estimate of how much a stock will move. It's expressed as an annualized percentage and is backed out of current option prices.
When options are expensive (high demand, big fear), IV is high. When options are cheap (low demand, calm market), IV is low.
The problem: saying "IV is 40%" doesn't tell you much without context. Is 40% high or low for this particular stock?
What is IV Rank?
IV Rank (IVR) answers the context question. It measures where current IV sits relative to its range over the past 52 weeks.
Formula:
IV Rank = (Current IV − 52-week Low IV) / (52-week High IV − 52-week Low IV) × 100
An IV Rank of 0 means current IV is at its lowest point of the past year. An IV Rank of 100 means it's at its highest. An IV Rank of 50 means it's exactly in the middle.
Why IV Rank matters for options sellers
Options sellers collect premium. More premium = more income potential. But not all high IV is the same.
A stock with IV at 40% might be expensive if its typical range is 15–25%. Or it might be cheap if its typical range is 50–80%. IV Rank tells you which.
High IV Rank (above 50): Options are expensive relative to history. This is generally when options sellers want to be active — premium is fat, mean reversion works in your favor, and the "volatility risk premium" (the tendency for realized vol to be lower than implied vol) is most pronounced.
Low IV Rank (below 30): Options are cheap. This is when option buyers have better odds — they're not overpaying for the move they're expecting.
IV Rank vs. IV Percentile
These terms are often confused:
- IV Rank uses the high and low of the range (described above)
- IV Percentile measures what percentage of trading days over the past year had lower IV than today
Both are useful. IV Percentile is less sensitive to outlier spikes — a single volatility event doesn't permanently distort the reading. IV Rank is simpler to calculate and widely quoted.
Most retail platforms (tastytrade, thinkorswim) show IV Rank. Use whichever your platform provides consistently.
Practical trading rules
A simple framework:
| IV Rank | Lean | Reasoning | |---------|------|-----------| | Above 50 | Sell premium | Options are expensive; vol tends to mean-revert | | 30–50 | Neutral | Either side can work depending on setup | | Below 30 | Buy premium or avoid | Options are cheap; selling offers thin margins |
This isn't a rigid rule — context matters. An earnings event, a merger, or a macro catalyst can keep IV elevated for legitimate reasons. But as a first filter, IV Rank helps you avoid the worst timing mistakes: selling premium when it's already depressed, or buying expensive options hoping for a move that's already priced in.
Tracking your IV Rank entries over time
Here's where most traders miss out. They know the theory but never audit whether they're actually following their own rules. Are you entering short premium trades at an average IV Rank of 60+? Or are you chasing trades at IV Rank 25 because the setup looked good?
Your trading journal should answer this question. Logging IV Rank at entry — position by position — lets you run an honest analysis after 50 or 100 trades. You might find that your best-performing trades cluster at high IV Rank entries. Or you might find your rules are looser than you thought.
Data beats intuition every time.