Most traders look at an option and see a bet on direction. I look at it and see a price for volatility. That price is implied volatility, and it’s the single biggest reason a trader can be right on direction and still lose money. I’m Don Kaufman. I started out pricing options as a market maker on the CBOE, and the first thing I learned on the dealer side is that the market makers aren’t paid for predicting direction. They’re paid for pricing volatility. Here’s how you can start thinking the same way.
What is implied volatility?
Implied volatility, or IV, is the volatility level built into an option’s price. It’s the market’s estimate of how much a stock will move over the next year, stated as a percentage.
It’s called “implied” because nobody publishes it. You back it out of the option’s price. Take the stock price, strike, time to expiration and interest rates, plug them into a pricing model, and the one number left that makes the model match the market price is the implied volatility.
So when options get more expensive with nothing else changing, implied volatility is rising. When they get cheaper, it’s falling. Option prices and implied volatility move together.
What the IV number actually means
An implied volatility of 30% means the market is pricing a one-standard-deviation move of about 30% over the next year. For a $100 stock, that’s a range of roughly $70 to $130 about 68% of the time.
Nobody trades on a one-year horizon, so here’s the shortcut I use every day:
The rule of 16
There are about 252 trading days in a year, and the square root of 252 is close to 16. So:
Daily expected move ≈ Implied volatility ÷ 16
If the VIX is at 16, the market is pricing about a 1% daily move in the S&P 500. If the VIX is at 32, it’s pricing about 2% a day. If a stock’s IV is 48%, the market expects about a 3% move per day.
That one division turns an abstract percentage into something you can see on a chart. To turn implied volatility into a dollar range for a specific expiration, use the expected move formula.
Implied volatility versus realized volatility
This is where the edge is.
- Implied volatility is what the market is pricing for the future.
- Realized volatility (also called historical volatility) is how much the stock actually moved over a past period.
When implied volatility is higher than what the stock ends up realizing, options were overpriced, and option sellers get paid. When realized volatility comes in higher than implied, options were cheap, and option buyers get paid.
Over long stretches, implied volatility tends to run a little higher than realized volatility. That gap is the insurance premium the market pays for protection. It’s the main reason option sellers who use defined risk and manage their size can have an edge over time. It’s also why buying options you hold to expiration is a tough game.
But “tends to” isn’t “always.” When the market gets hit by a real shock, realized volatility can blow straight through implied. That’s why I never sell premium without a defined maximum loss.
IV rank and IV percentile
A 40% IV is high for a utility stock and low for a biotech. To know whether implied volatility is expensive, compare it to the stock’s own history:
- IV rank shows where today’s IV sits between its 52-week low and high. The formula is (Current IV − 52-week low) ÷ (52-week high − 52-week low). An IV rank of 80 means IV is near the top of its one-year range.
- IV percentile shows the percentage of days over the past year when IV was lower than today. An IV percentile of 80 means IV was lower 80% of the time.
Both tell you the same basic thing: is volatility rich or cheap for this name right now? When it’s rich, I lean toward selling premium with defined risk. When it’s cheap, I’d rather own options or use structures that benefit if volatility rises.
Volatility skew
Implied volatility isn’t the same at every strike. In index options, out-of-the-money puts usually carry higher implied volatility than out-of-the-money calls. Traders pay up for crash protection. That difference across strikes is called skew.
Skew matters because it changes which strikes are rich. If you’re selling puts on SPX, you’re often selling the most expensive part of the chain, which is good for collecting premium but also where the risk is concentrated. When skew flips and calls get pricier than puts, the market is telling you something unusual is happening. Pay attention.
IV crush around earnings
Before an earnings report, traders bid up the front-month options and implied volatility climbs. Once the report is out, the uncertainty is gone and implied volatility collapses, often overnight. That’s IV crush.
IV crush is why buying calls before earnings so often disappoints. The stock moves the right way, but the drop in implied volatility takes more out of the option’s price than the move adds. It’s also why structures where you’re short the options carrying the most earnings premium, like the butterflies in my Earnings Flips service, can benefit from the crush instead of fighting it. You can see a full example in the expected move article.
How implied volatility affects your options: vega
Vega measures how much an option’s price changes for each one-point change in implied volatility. If an option has a vega of 0.10 and IV rises from 30% to 31%, the option gains about $0.10.
- When you buy options, you’re long vega. Rising IV helps you, and falling IV hurts.
- When you sell options, you’re short vega. Falling IV helps you.
Longer-dated options have more vega than shorter-dated ones, so a change in implied volatility moves a six-month option much more than a one-week option. Know your vega before you enter, the same way you know your direction.
How I trade implied volatility
1. Rich volatility: sell it, with defined risk. When IV rank is high and implied volatility is running well above realized, I look for credit spreads, iron condors, butterflies and Christmas tree spreads that profit if the stock moves less than the market is pricing.
2. Cheap volatility: own it. When implied volatility is low and the market looks complacent, I’d rather be long options, or use calendars and diagonals that benefit if volatility rises.
3. Watch the cycles. Volatility mean-reverts. It spikes, then settles back down, then spikes again. Timing those turns is the whole idea behind Shadow Clocks, my volatility timing indicator.
4. Respect the VIX. The VIX is the market’s 30-day implied volatility on S&P 500 options. I check it every morning. It sets the tone for how rich or cheap options are across the board.
Common implied volatility mistakes
- Ignoring IV when buying options. A great directional call can still lose money if you overpaid for volatility.
- Selling cheap volatility. Selling premium when IV is near its lows means taking on the same risk for less pay.
- Comparing IV across different stocks. Use IV rank or percentile to judge whether a stock’s IV is high for that stock.
- Forgetting the earnings date. An expiration that includes earnings will show much higher IV, and it will drop after the report.
- Selling without defined risk. Implied volatility is usually overpriced, until the day it isn’t.
Implied volatility FAQ
Is high implied volatility good or bad?
Neither. High IV means options are expensive, which is better for sellers. Low IV means options are cheap, which is better for buyers.
What’s the difference between implied and historical volatility?
Implied volatility is forward-looking and comes from option prices. Historical volatility measures how much the stock actually moved in the past.
What does the VIX measure?
The VIX measures the 30-day implied volatility priced into S&P 500 options. Divide it by 16 for the market’s expected daily move.
What is a good IV rank to sell options?
Many traders look for an IV rank above 50 before selling premium, but it depends on the stock and the strategy. Always use defined risk.
Start reading implied volatility today
Before your next trade, check three things: the IV, its IV rank, and the expected move. If you’re buying, make sure you aren’t overpaying. If you’re selling, make sure you’re getting paid enough for the risk.
I break down volatility on real trades every trading day in Don’s Trading Desk, free. For a deeper dive, the VIX Volatility Mega-Bundle has 97 sessions on volatility and the VIX. To get trades built on this framework, see my services.
Trading options involves substantial risk of loss and is not suitable for all investors. This article is for education only and is not investment advice.
