Contract size refers to the standardized quantity of the underlying asset represented by a single futures, options, or derivative contract. It determines the total value of the position and varies by instrument — for example, one standard forex lot is 100,000 units of the base currency, while one gold futures contract on COMEX represents 100 troy ounces.
Example
“The contract size for WTI crude oil futures is 1,000 barrels, so a $1 move in the oil price results in a $1,000 gain or loss per contract.”