What does Contract Size mean?
The amount of underlying asset represented by each futures contract. Contract size is the number or the quantity for any underlying contract. It is standardized and pre-defined by exchanges. It is the lot or amount of a commodity or financial instrument which can be traded in a futures or option market.
Futures Knowledge Explains Contract Size
In futures markets the contract sizes for options for stocks are uniform. But In the case of the commodities, contract sizes are different for different commodities and vary across exchanges. The contract size is reviewed periodically and depending on the current market price it is changed.