A call is a contract that gives you the right to buy a stock at a set price by a certain date

When you buy a call option, you are paying for the right — but not the obligation — to purchase 100 shares of a specific stock at a fixed price, called the strike price. That right expires on a specific date. If the stock price rises above your strike price before that date, you can exercise the call and buy the shares at the lower locked-in price, then sell them at the higher market price and pocket the difference. If the stock price falls or stays flat, you simply let the call expire and lose only the money you paid for it upfront.

Calls are used by traders and investors in two main ways: to bet that a stock will go up in price, or to reduce the cost of buying shares you already plan to own. A call costs far less than buying the stock outright, which means you can control a larger position with less money — but it also means you can lose your entire investment if the stock moves the wrong way.

Key Takeaways

  • A call option gives you the right to buy 100 shares of a stock at a fixed strike price before the expiration date.
  • You pay an upfront premium to buy a call, and that is the maximum amount you can lose if the stock price falls.
  • If the stock price rises above the strike price, you can exercise the call to buy shares at the lower price and sell them at a profit.
  • Calls expire on a specific date, and any right to buy at that strike price disappears if you do not exercise before then.
  • Call options let you control more shares with less money than buying stock directly, but they carry higher risk because your entire premium can be lost.

How the strike price and expiration date work together

The strike price is the price at which you have the right to buy the stock. It stays the same for the entire life of the call, regardless of what the stock actually trades for in the market. For example, if you buy a call with a strike price of $50 on a stock currently trading at $48, you have locked in the right to buy at $50 even if the stock later jumps to $75.

The expiration date is when your right to buy expires. Most stock options expire on the third Friday of the month, though some expire weekly or daily. Once that date passes, the call is worthless and you cannot exercise it anymore. This is why time matters: as expiration approaches, the call loses value even if the stock price stays the same, because there is less time for the stock to move in your favor.

What you pay upfront and what you can lose

The premium is the price you pay to buy the call option. It is quoted per share but you actually pay 100 times that amount, since one call contract controls 100 shares. If a call is quoted at $2.50, you pay $250 total ($2.50 × 100). This premium is the maximum you can lose — if the stock price falls and never recovers, you simply let the call expire and walk away having lost your $250.

The premium is not a down payment on the stock. It is the full cost of the right itself, and it goes to the person who sold you the call, not toward any future purchase. If you later exercise the call and buy the shares, you pay the strike price in full, separate from the premium you already paid.

When a call makes money and when it does not

A call makes money when the stock price rises above the strike price plus the premium you paid. If you paid a $2.50 premium for a $50 strike call, the stock needs to reach $52.50 just to break even. Every dollar above $52.50 at expiration is profit (up to the point where you exercise and sell). If the stock is below $50 at expiration, the call expires worthless and you lose the entire premium.

The relationship between the current stock price and the strike price determines whether a call has intrinsic value right now. If the stock is trading at $55 and your strike is $50, your call is worth at least $5 per share ($500 total) because you could exercise immediately and pocket that difference. If the stock is trading at $48 and your strike is $50, your call has no intrinsic value — it is worth only the time value remaining before expiration, which is whatever traders are willing to pay for the chance that the stock will rise.

The difference between buying a call and selling a call

When you buy a call, you pay the premium upfront and your maximum loss is that premium. Your profit potential is theoretically unlimited — if the stock soars to $200, your $50 strike call is worth $150 per share. This is a bullish bet: you win if the stock goes up.

When you sell a call (also called writing a call), you collect the premium upfront but you take on the obligation to sell the stock at the strike price if the buyer exercises. Your maximum profit is the premium you collected, but your loss can be large if the stock rises sharply. Selling calls is a bearish or neutral bet: you win if the stock stays flat or falls, but you lose if it rises significantly. Most beginning traders should focus on buying calls, not selling them, because the risk structure is simpler.

How calls fit into a trading strategy

Traders use calls to bet on upward price movement with less capital than buying the stock outright. Instead of spending $5,000 to buy 100 shares of a $50 stock, you might spend $250 on a call and keep the rest of your money for other trades or to cover losses. The tradeoff is that your call can expire worthless, whereas the stock itself could recover.

Investors who already own a stock sometimes sell calls against their shares to generate extra income from the premium. This is called a covered call because you own the underlying stock and can deliver it if the call is exercised. It reduces your upside if the stock soars, but it gives you cash now and protects you slightly if the stock falls.

Calls are also used in combination with other options to create strategies with specific risk and reward profiles — for example, buying a call and selling a call at a higher strike price to reduce your net cost. These strategies are more complex and require understanding how multiple options interact.

Why call prices change before expiration

A call's premium changes based on four main factors: the stock price, the time remaining until expiration, how much the stock price is expected to move (called volatility), and interest rates. When the stock price rises, the call becomes more valuable. When the stock price falls, the call becomes less valuable. As expiration approaches, the call loses time value — the premium shrinks even if nothing else changes, because there is less time for the stock to move in your favor.

High volatility makes calls more expensive, because there is a greater chance the stock will move above the strike price. Low volatility makes calls cheaper. This is why call prices can swing significantly even on days when the stock price barely moves — traders are repricing the call based on their expectations of future movement.

Frequently Asked Questions

What happens if I buy a call and the stock price never reaches the strike price?

The call expires worthless and you lose the entire premium you paid. You do not owe anything else and you do not have to buy the stock. Your loss is capped at the amount you spent upfront.

Can I sell a call I bought before expiration?

Yes. You do not have to hold a call until expiration or exercise it. You can sell it back to the market at any time during trading hours. If the stock has risen, your call will be worth more than you paid and you can lock in a profit. If the stock has fallen, you can sell it for whatever it is worth and cut your loss.

What is the difference between a call and a put?

A call gives you the right to buy a stock at a set price. A put gives you the right to sell a stock at a set price. Calls are bullish bets that the stock will rise. Puts are bearish bets that the stock will fall.

Do I need to own the stock to buy a call?

No. You can buy a call on any stock without owning it. You are simply buying the right to purchase it at the strike price. If you exercise, you will need the money to pay the strike price, but you do not need to own the stock beforehand.

What does it mean if a call is "in the money"?

A call is in the money when the stock price is above the strike price. It has intrinsic value — you could exercise it immediately and make money. A call is out of the money when the stock price is below the strike price and has no intrinsic value, only time value.