How to Read an Options Chain:
Every Column Decoded

Before you place your first options trade, you need to be able to read the options chain. It's the grid your broker displays that lists every available option for a given stock — organized by expiration date and strike price. At first glance it looks like a spreadsheet full of numbers. After this article, every column will make immediate sense.

We'll use a real-world example throughout: AAPL trading at $185.00, looking at the 30-day expiration chain.

How the Chain Is Laid Out

Every options chain has the same basic structure. The calls are on the left side, the puts are on the right, and the strike prices run down the middle column. The chain is organized so that at-the-money (ATM) strikes sit in the middle, with in-the-money (ITM) options above (for calls) and below (for puts) the current stock price.

The Key Columns Explained

Bid / Ask

The bid is the highest price a buyer is willing to pay right now. The ask (or offer) is the lowest price a seller will accept. When you buy an option, you pay the ask. When you sell, you receive the bid. The difference between them — the bid/ask spread — is your immediate cost of entry.

Always use limit orders at the mid-price rather than market orders. A market order on an illiquid option can fill at the ask (or worse), instantly costing you more than necessary. Most brokers will fill limit orders at mid or better on liquid names like AAPL.

Last

The last traded price. This can be misleading — options on low-volume strikes may not have traded for hours, making the "last" price stale. Always look at the bid and ask to understand where the market actually is right now.

Volume

The number of contracts traded today. Volume resets to zero at the start of each session. High volume means there's active interest in that specific strike — good for liquidity and tighter bid/ask spreads. Low volume means you may struggle to fill at a reasonable price.

Open Interest (OI)

Open interest is the total number of outstanding contracts that have not been closed or exercised. Unlike volume, it does not reset daily — it builds over time as traders open positions and falls as they close them. High open interest at a specific strike often indicates that many traders see that level as significant, making it a useful reference for support and resistance.

Implied Volatility (IV)

Implied volatility is the market's forward-looking estimate of how much the stock will move, expressed as an annualized percentage. It's derived from the option's current market price using an options pricing model. Higher IV means more expensive options — the market expects bigger moves. Lower IV means cheaper options.

IV is listed per strike and varies across the chain — this variation is called the volatility smile or skew. Put options typically have higher IV than equivalent calls because traders pay a premium for downside protection. This is why out-of-the-money puts are often more expensive than out-of-the-money calls at the same distance from the stock price.

Notice how puts carry higher IV than calls at equivalent distances from the current price — this is the standard put skew. It means selling OTM puts collects more premium relative to the probability of expiring worthless, which is one reason income traders favor put-selling strategies.

Delta

Delta measures how much the option's price changes for every $1 move in the underlying stock. A delta of 0.50 means the option gains (or loses) $0.50 for every $1 move in the stock. Delta also serves as a rough probability proxy — a 0.20 delta option has approximately a 20% chance of expiring in-the-money.

• ATM options have a delta of approximately 0.50
• Deep ITM options have a delta approaching 1.00 (move almost dollar-for-dollar with stock)
• Deep OTM options have a delta close to 0.00 (barely respond to stock moves)

Reading Expiration Dates

Options chains are organized by expiration date. Most stocks offer weekly expirations (every Friday), monthly expirations (third Friday of each month), and sometimes quarterly or LEAPS (long-dated, 1–2 years out). Each expiration date has its own complete chain of strikes.

Days to Expiration (DTE) tells you how much time value remains. The further out the expiration, the more expensive the option — more time means more opportunity for the stock to move. Options traders track DTE carefully because time decay (theta) accelerates sharply in the final 30 days.

Choosing the Right Strike

With dozens of strikes available for each expiration, selecting the right one comes down to your objective:

• Speculative directional trade (buying calls/puts): Look at 30–50 delta strikes (near ATM). Higher delta means the option responds more strongly to the move you're predicting, but costs more premium.
• Income / premium selling (covered calls, CSPs): Sell 15–30 delta strikes (OTM). Lower delta means higher probability of expiring worthless — you keep the premium more often.
• Defined-risk spreads: Sell the 20–25 delta strike, buy the next strike further OTM as protection. This caps both risk and reward.

Putting It All Together

When you open an options chain, run through this checklist before placing any trade:

1. Check liquidity — volume and open interest confirm you can enter and exit efficiently.
2. Read the bid/ask spread — wide spreads on illiquid options cost you before the trade even moves.
3. Check IV relative to history — high IV? Consider selling strategies. Low IV? Consider buying strategies.
4. Select expiration by strategy — 30–45 DTE for selling, 45–90 DTE for buying.
5. Choose strike by delta — delta guides both sensitivity and probability.
6. Use limit orders at mid — never use market orders on options.