How to read an option chain
Strikes, bid/ask, open interest, and volume — decoded, with a live real chain to practice on.
An option chain lists every call and put available for a stock at a given expiry, organized by strike price. For each contract you'll see a bid and ask price, open interest (how many contracts are currently open), and volume (how many traded today). Reading a chain well is really just reading five things together: strike versus the stock price, bid/ask spread, open interest, volume, and how those compare to nearby strikes.
Strikes, and what ITM/OTM mean
Every row in a chain is one strike price. A call is in-the-money (ITM) if the strike is below the current stock price — it already has intrinsic value, since you could theoretically exercise it for an immediate profit. A call is out-of-the-money (OTM) if the strike is above the stock price — it has no intrinsic value yet, only extrinsic (time and volatility) value. Puts work in reverse: ITM when the strike is above the stock price, OTM when below.
Bid, ask, and the spread
Every contract quotes two prices: the bid (the most a buyer is currently offering) and the ask (the least a seller will currently accept). You buy at the ask and sell at the bid — the gap between them is the spread, and it's a direct read on liquidity. A tight spread (a few cents on a multi-dollar option) means it's cheap to get in and out; a wide spread means real trading costs even before the stock moves.
Open interest vs volume
These two numbers get confused constantly, but they measure different things. Volume is how many contracts changed hands today. Open interest is how many contracts are currently open — accumulated across every day since that contract started trading, only decreasing when positions are closed or the contract expires. High open interest at a strike means a lot of standing positioning there; high volume relative to that open interest can signal something is happening right now. See Open interest vs volume for the full breakdown, including what it means when volume actually exceeds open interest.
Common mistakes
Trading options with a wide bid/ask spread. A contract can look cheap on the ask and still cost you real money just crossing the spread to get in and back out.
Confusing high volume with high open interest. A contract can trade heavily today (volume) while still having modest total open positioning (open interest), or vice versa — check both.
Ignoring the whole chain in favor of one strike. Liquidity, skew, and unusual activity patterns only become visible when you scan several strikes and both expirations at once, not one row in isolation.
Try it live
The chain below is real — five real strikes from OptionScope's live CBOE-fed chain, centered on the money, at the expiry closest to 30–45 days out. Look up any symbol:
Open the full Option Chain — free →
Related: Open interest vs volume · The options Greeks · Deep dive: reading a chain