What Is an Option? The Right, Not the Obligation, Explained in Plain English

An option is a contract that gives its buyer the right, but not the obligation, to buy or sell an asset at a fixed price on or before a fixed date. The buyer pays a price called the premium for that right, and the seller (the writer) takes on the obligation to complete the trade if the buyer chooses to use it.

In short: a listed stock option is a standardized contract that usually covers 100 shares. A call gives the right to buy at the strike price; a put gives the right to sell at the strike price. The buyer’s maximum loss is the premium paid. The writer collects the premium up front and, in exchange, must buy or sell the shares if assigned. Every option has an expiration date, after which the right disappears.

A common misconception

Many people meet options through a broker app that shows a price like “$2.60” next to a contract and assume that is what the trade costs. It isn’t. Stock option premiums are quoted per share, and a standard contract covers 100 shares. A $2.60 quote means the contract costs $2.60 x 100 = $260, before commissions and fees. That multiplier is the single most important number for a newcomer, because every gain and every loss gets multiplied by it too.

The four parts of every option

Every listed option is defined by four things:

The underlying. The stock, exchange-traded fund (ETF), or index the option is based on.
The type. A call (right to buy) or a put (right to sell).
The strike price. The fixed price at which the shares can be bought or sold. See strike prices and expiration dates for how strikes are listed.
The expiration date. The last day the right exists. For standard monthly US equity options, that is normally the third Friday of the month.

Change any one of these and you have a different contract with a different price.

Buyers and writers

Each option has two sides, and they have very different positions:

	Buyer (holder, “long”)	Writer (seller, “short”)
Pays or receives premium	Pays	Receives
Has a right or an obligation	Right	Obligation
Maximum loss	The premium paid	Large; unlimited for a call written without owning the shares
Maximum gain	Large; unlimited for a call	The premium received
Decides whether to exercise	Yes	No; may be assigned

The buyer chooses whether to use (exercise) the option. The writer has no say: if the buyer exercises, the writer is assigned and must deliver or take delivery of the shares at the strike. How that matching happens is covered in how exercise and assignment work.

Most options positions are never exercised by choice. Holders usually close them by selling the contract back into the market before expiration, and writers close by buying it back.

Calls and puts in one paragraph each

A call rises in value when the underlying price rises. If you hold a call with a $50 strike and the stock is at $60 at expiration, the right to buy at $50 is worth about $10 per share, or $1,000 per contract. The full mechanics are in call options explained.

A put rises in value when the underlying price falls. If you hold a put with a $50 strike and the stock is at $40 at expiration, the right to sell at $50 is worth about $10 per share, or $1,000 per contract. See put options explained.

A worked example

Take a hypothetical company, Maple Widgets Inc., trading at $50. Suppose a call with a $55 strike expiring in about two months is quoted at $0.85.

Cost to the buyer: $0.85 x 100 = $85.
Breakeven at expiration: strike plus premium, $55 + $0.85 = $55.85.
What the writer receives: $85, and the obligation to sell 100 shares at $55 if assigned.

Value and profit for the buyer at expiration:

Maple price at expiry	Call value per share	Contract value	Buyer’s profit or loss	Writer’s profit or loss
$45	$0	$0	-$85	+$85
$50	$0	$0	-$85	+$85
$55	$0	$0	-$85	+$85
$55.85	$0.85	$85	$0	$0
$60	$5.00	$500	+$415	-$415
$70	$15.00	$1,500	+$1,415	-$1,415

Read the table both ways. The buyer loses the whole $85 in most of the scenarios shown, because the stock has to rise more than 11% just to break even. The writer keeps $85 in those same scenarios but faces losses that grow by $100 for every dollar the stock rises above the breakeven. Options are a zero-sum contract between the two sides before costs: one side’s gain is the other side’s loss, and commissions and the bid-ask spread make the total slightly negative.

Why options exist

Options are not a recent invention, but listed, standardized options are. The Chicago Board Options Exchange (now Cboe) opened on April 26, 1973, as the first US exchange for listed options, trading calls on 16 stocks. Listed puts followed in 1977. The clearing house that became The Options Clearing Corporation (OCC) was set up the same year Cboe opened.

People use options for a few distinct reasons:

Hedging. A shareholder can buy a put to set a floor under a position, much like buying insurance. A farmer, a pension fund, and a company with stock compensation all have versions of this need.
Defined-risk exposure. A call buyer can gain from a rise in price while risking only the premium, instead of the full cost of the shares.
Collecting premium. Writers accept an obligation in exchange for cash now. This is how covered calls and cash-secured puts work, and it carries real risk.
Transferring risk. At bottom, an options market moves price risk from people who don’t want it to people who are paid to take it.

What options are not is a shortcut to easy money. The leverage that makes a call cheap compared with the shares also means the premium can go to zero quickly. Losing the full premium is a normal outcome for a buyer, not a rare one, which is covered honestly in options risks explained honestly.

What the premium is paying for

The premium has two parts. Intrinsic value is what the option would be worth if exercised right now (zero for the $55 call above, because the stock is at $50). Extrinsic value, or time value, is everything else: what buyers pay for the chance that the price moves past the strike before expiration. Time value shrinks as expiration approaches. How option premiums work explains what moves each part.

Standardization: why a listed option is the same everywhere

Listed options in the US are standardized: the exchange sets the contract size, the strikes, and the expiration dates, and OCC acts as the issuer and guarantor of every contract. When you buy an option, your contract is effectively with OCC, not with the specific person who sold it. That is why you can sell an option on one exchange that you bought on another.

In Canada, listed equity options trade on the Montréal Exchange and are cleared by the Canadian Derivatives Clearing Corporation (CDCC). A Montréal Exchange equity option also represents 100 shares and is American style, meaning it can be exercised on any business day up to expiration.

Before a US broker can approve you to trade options, it must give you the Options Disclosure Document, formally titled Characteristics and Risks of Standardized Options, published by OCC. FINRA Rule 2360 requires delivery at or before the time the account is approved for options. It is long, but the risk sections are worth reading.

What can go wrong

Losing the entire premium. For a buyer, this is common, not rare. An option can be right about direction and still lose if the move is too small or too late.
Forgetting the multiplier. A $3 move in an option price is a $300 move in your account per contract.
Unexpected assignment. Writers of American-style options can be assigned before expiration, not just on the last day.
Large losses for writers. A call written without owning the shares has no ceiling on its potential loss.
Illiquid contracts. Some options have wide gaps between the bid and ask prices, so getting in and out costs more than the quoted price suggests.

Common questions

Are stock options from my employer the same thing?

No. Employee stock options are issued by a company to its staff, can’t be traded on an exchange, usually vest over time, and are taxed under separate rules. Listed options are standardized contracts that anyone with an approved account can buy or sell, and the company whose shares they’re based on isn’t involved at all.

Do I need a lot of money to trade options?

A single contract can cost less than a share of some stocks, which is part of the appeal and part of the danger. Writing options, especially uncovered ones, requires margin and higher approval levels. Brokers assess experience, finances, and objectives before granting each level.

The takeaway

An option is a time-limited right to buy (call) or sell (put) a set number of shares, usually 100, at a fixed strike price. Buyers pay a premium for that right and can lose all of it. Writers collect the premium and take on an obligation that can cost far more. Understanding the multiplier, the breakeven, and which side of the contract you are on is the starting point for everything else on this site.