What an option actually is
An option is a contract between two people about a future transaction. The buyer pays money up front, called the premium, and in exchange gets the right to buy or sell 100 shares of a stock at a fixed price until a fixed date. The seller collects that premium and takes on the obligation to complete the transaction if the buyer decides to use it.
Every contract is defined by four things:
- The underlying, which is the stock the contract is written on.
- The strike price, the fixed price at which shares can be bought or sold.
- The expiration date, after which the contract no longer exists.
- The premium, the market price of the contract itself.
Call options
A call gives its owner the right to buy 100 shares at the strike price. You buy a call when you think the stock is going up, because the right to buy at $100 becomes more valuable as the stock climbs above $100.
Suppose a stock trades at $100 and you buy a call with a $105 strike expiring in 30 days for $2.40 per share, or $240 total. If the stock finishes at $115, your right to buy at $105 is worth $10 per share, so the contract settles for $1,000 and your profit is $760. If the stock finishes anywhere at or below $105, nobody wants the right to buy at $105 when the market offers a better price, so the contract expires worthless and you lose the $240 you paid.
Notice the shape. The downside is flat, because the most you can lose is what you paid. The upside is a straight diagonal line with no ceiling, which is why calls attract people looking for leverage. That $240 controls $10,000 of stock exposure, so a 15% move in the stock produced a 317% return on the option.
Put options
A put is the mirror image. It gives its owner the right to sell 100 shares at the strike price, so it gains value as the stock falls. People buy puts either to speculate on a decline or to insure shares they already own, which is where the nickname "portfolio insurance" comes from.
Using the same $100 stock, a $95 strike put expiring in 30 days might cost $2.10 per share, or $210. If the stock drops to $85, the right to sell at $95 is worth $10 per share and the contract settles for $1,000. If the stock stays above $95, the put expires worthless.
The put has a maximum profit that the call does not, because the stock can only fall to zero. That ceiling matters when you price the two: all else equal, the bounded payoff is one reason puts and calls at equivalent distances do not cost exactly the same.
The four basic positions
Every options position, no matter how complicated, is built from four building blocks. You can buy or sell each of the two contract types.
| Position | You profit when | Max profit | Max loss |
|---|---|---|---|
| Long call (buy a call) | Stock rises above break-even | Unlimited | Premium paid |
| Long put (buy a put) | Stock falls below break-even | Strike minus premium | Premium paid |
| Short call (sell a call) | Stock stays below strike | Premium received | Unlimited |
| Short put (sell a put) | Stock stays above strike | Premium received | Strike minus premium |
The asymmetry in that table is the whole game. Buyers have small defined losses and large uncertain gains, and they are wrong most of the time. Sellers have small defined gains and large uncertain losses, and they are right most of the time. Neither side is automatically better, because the market prices that trade-off.
Finding the break-even price
Break-even is the stock price at expiration where you neither make nor lose money, and it is the number that turns a vague opinion into a testable one. The arithmetic is simple:
The $105 call bought for $2.40 breaks even at $107.40, which means the stock has to rise 7.4% in 30 days before you make a dollar. Being right about direction is not enough. You have to be right by more than the premium, before the clock runs out.
Our break-even calculator does this for any real contract, including the required percentage move from the current price, and the options profit calculator shows what the position is worth at every price on every date before expiration, not just at the end.
What happens at expiration
At expiration, an option is worth only its intrinsic value, meaning how far in the money it is. All time value is gone. Three outcomes are possible:
- Out of the money. The contract expires worthless. Buyers lose the premium, sellers keep it.
- In the money. Most brokers automatically exercise contracts that finish more than $0.01 in the money, so a long call becomes 100 shares purchased at the strike, and a short call means delivering 100 shares.
- Closed early. You sell the contract before expiration and collect its market value, which is what most traders actually do.
Where beginners lose money
Three failure modes account for most early losses, and none of them is about picking the wrong direction.
Ignoring time decay. An option loses value every day the stock does nothing, and the loss accelerates in the final weeks. A position can be directionally correct and still lose money because the move arrived too slowly.
Buying expensive volatility. Premiums inflate ahead of earnings and other scheduled events. When the news lands, implied volatility collapses and the option can lose value even when the stock moves your way. This is covered in our implied volatility guide.
Sizing by contract count. Five contracts sounds small, but five $2.40 calls is $1,200 that can go to zero entirely. Size positions by the dollars at risk, not by how many contracts feel reasonable.