Where f is the present value of futures, f is the real-time price of futures, k is the delivery price of futures, r is the risk-free rate of return, and t is the time from now to the delivery date.
In addition, we should understand the difference between futures and forwards. There is no cash exchange at the beginning of the contract signing, and its value will be realized only at the end of the contract, that is, the delivery date (K-S or physical delivery according to K).