What Is a Contract?

In trading, a contract usually means one standard unit of a derivative, such as one futures contract or one options contract. Unlike shares, which you can buy one at a time, contracts come in fixed sizes set by the exchange. Knowing exactly how much one contract controls is the first step to sizing positions safely, because a single contract can represent tens or hundreds of thousands of dollars of exposure.

Contracts are standardised#

Exchanges define every detail of each contract so that all contracts of the same type are identical and interchangeable. That standardisation is what allows thousands of traders to buy and sell the same contract on an open market. The key terms are published in the contract specifications. See Contract Specifications.

The multiplier: turning price into money#

The multiplier converts the quoted price into the contract's money value.

Contract value = Price × Multiplier

That last point confuses many beginners: an option price shown as $2.50 is per share, so one contract costs $250 plus fees.

Why contract size matters for risk#

Because one contract can be large, a small price move can create a large gain or loss. You must translate your risk plan into contracts, not into dollars of margin.

This is why exchanges list micro and mini versions of popular contracts: they let smaller accounts size positions sensibly. See Position Sizing and Tick Size and Tick Value.

Contracts in other markets#

• Forex: positions are sized in lots. A standard lot is 100,000 units of the base currency, a mini lot 10,000 and a micro lot 1,000. See Lots: Standard, Mini and Micro.
• CFDs: usually sized in units of the underlying, such as shares or ounces, set by the broker.
• Crypto perpetual futures: contract sizes vary by exchange; some quote in coins, others in dollars.
• Prediction markets: you trade shares that each pay $1 if an outcome happens, so the "contract" is one share.

Open interest and volume in contracts#

For futures and options, activity is measured in contracts. Volume is how many contracts traded in a period, and open interest is how many contracts remain open. Both help judge liquidity and participation. See Volume and Open Interest.

Common mistakes#

• Confusing margin with exposure. A $1,500 margin requirement does not mean you are risking $1,500; you are controlling the full contract value.
• Forgetting the option multiplier and buying ten contracts thinking each costs the quoted price.
• Sizing by "one contract" by default. Size from your stop and multiplier, and use micro contracts when one full contract is too large.

Frequently asked questions#

How many shares is one option contract?#

Standard US stock and ETF options cover 100 shares per contract, though adjustments after corporate events can change this for specific contracts.

What does contract multiplier mean?#

It is the number that converts the quoted price into the money value of one contract, for example $50 per index point for the E-mini S&P 500.

Can I trade less than one futures contract?#

Not on a futures exchange, but many contracts have mini and micro versions that are a fraction of the size, and some brokers offer CFDs or ETFs for smaller exposure.

Sources#

• Wikipedia, Futures contract
• U.S. Securities and Exchange Commission, Options