Options 101: Calls, Puts, and How They Actually Work

A technical but accessible introduction to options — contracts, strike prices, expiration, intrinsic vs extrinsic value, assignment, and the real math behind payoff diagrams.

Options are contracts that let you control 100 shares of stock for a fraction of the cost of owning them outright. That leverage is the reason options can multiply wealth quickly — and also why they destroy retail accounts faster than almost any other financial product. Before you trade a single contract, you need to understand exactly what you are buying, how it is priced, and what can go wrong. This guide covers the fundamentals with actual dollar math and no hand-waving.

What an Options Contract Actually Is

An options contract gives the buyer the right — but not the obligation — to buy or sell 100 shares of a stock at a specific price, on or before a specific date. The seller of the contract takes on the obligation in exchange for the premium paid upfront.

• Call option — right to BUY 100 shares at the strike price. Bullish bet.
• Put option — right to SELL 100 shares at the strike price. Bearish bet or hedge.
• Strike price — the agreed-upon buy/sell price written into the contract.
• Expiration — the last day the option can be exercised. Weekly, monthly, quarterly, or LEAPS (1-3 years).
• Premium — the price to buy or sell the contract, quoted per share (×100 for dollar cost).

Intrinsic Value vs Extrinsic Value

Every option's premium breaks down into two components. Understanding the split is the foundation of everything that follows.

• Intrinsic value — how much in-the-money the option is RIGHT NOW. A $100 call with stock at $105 has $5 of intrinsic value.
• Extrinsic value (time value) — everything else. It decays to zero at expiration.
• In-the-money (ITM) — call strike below stock price, or put strike above stock price. Has intrinsic value.
• Out-of-the-money (OTM) — call strike above stock price, or put strike below stock price. All premium is extrinsic.
• At-the-money (ATM) — strike near current price. All premium is extrinsic; highest time value.

The Call Option Payoff — Worked Example

Assume XYZ trades at $100. You buy the 30-day $100 call for $3.00 ($300 per contract). Your max loss is $300 (the premium). Your break-even at expiration is $103 (strike + premium).

• At $95 at expiry — call expires worthless. Loss: -$300 (-100%).
• At $100 at expiry — call expires worthless. Loss: -$300 (-100%).
• At $103 at expiry — intrinsic value is $3, matching premium. Break-even (-$0).
• At $110 at expiry — intrinsic value is $10. Profit: $700 per contract (+233%).
• At $120 at expiry — intrinsic value is $20. Profit: $1,700 per contract (+567%).
• Above $100 before expiry — profit also includes remaining time value.

The Put Option Payoff — Worked Example

Same XYZ at $100. You buy the 30-day $100 put for $2.80 ($280 per contract). Max loss is $280. Break-even at expiration is $97.20 (strike - premium).

• At $105 at expiry — put expires worthless. Loss: -$280.
• At $100 at expiry — put expires worthless. Loss: -$280.
• At $97.20 at expiry — break-even.
• At $90 at expiry — intrinsic value is $10. Profit: $720 per contract (+257%).
• At $80 at expiry — intrinsic value is $20. Profit: $1,720 per contract (+614%).
• The put's max theoretical gain is capped at (strike × 100 - premium) if stock goes to zero.

Writing (Selling) Options — The Other Side of the Trade

When you buy a call or put, someone is writing it to you. Writers collect the premium upfront but take on the obligation to buy or deliver shares if exercised. The risk profile flips.

• Covered call — sell a call against 100 shares you already own. Max profit: premium + (strike - cost basis). Risk: capped upside if stock rallies past strike.
• Cash-secured put — sell a put and hold cash equal to 100 × strike. Max profit: premium. Risk: forced to buy 100 shares at strike if assigned.
• Naked call — sell a call without owning shares. Unlimited loss potential. Requires high-tier options approval and significant margin.
• Naked put — sell a put without cash to buy shares. Loss capped at strike × 100 - premium (stock can only go to zero).
• Assignment — if the option goes in-the-money at expiration, the buyer exercises and the writer must deliver shares (call) or buy them (put) at the strike price.

Assignment, Exercise, and Settlement

• Exercise — the option buyer elects to convert the contract into shares. Usually happens at or near expiration when ITM.
• Assignment — the writer is randomly selected by the Options Clearing Corporation to fulfill the exercise. You cannot predict or prevent it beyond closing the contract.
• Early assignment — American-style options (most single-name stocks) can be assigned any time before expiration. European-style (index options like SPX) can only be assigned at expiration.
• Automatic exercise — brokers auto-exercise any option $0.01+ ITM at expiration unless you instruct otherwise.
• Pin risk — when stock closes very near the strike at expiration, assignment can be unpredictable. Close positions before expiration to avoid it.
• Dividends — call writers risk early assignment the day before an ex-dividend date if the call is deep ITM. Check ex-div calendars.

Key Takeaways

• One options contract controls 100 shares — the dollar risk is always premium × 100.
• Premium = intrinsic value + extrinsic (time) value. Extrinsic decays to zero at expiration.
• Buyers have defined risk but pay theta; sellers collect theta but face larger tail risk.
• Implied volatility drives option prices as much as the stock itself — sell high IV, buy low IV.
• Stick to liquid underlyings, 30-60 DTE, and 2-3% per trade until you have 30+ live trades of experience.