Contract multiplier, also known as contract size or contract unit, refers to the standardized trading unit size of futures contracts or option contracts. It is a fixed value set by the exchange, which is used to determine the transaction scale and price calculation of each contract.

For futures contracts, the contract multiplier represents the number of underlying assets represented by each contract, and the calculation unit is tons.

For option contracts, the contract multiplier represents the number of underlying assets controlled by each contract. For example, the contract multiplier of a standard stock option contract is usually 10000.

The existence of contract multiplier makes the trading of futures contracts and option contracts standardized and convenient. It ensures that the trading volume and price of each contract are carried out on a unified basis, which facilitates the trading of traders and ensures the liquidity of the market.