How do we calculate the profit/loss of Futures contract? For example, If I had a Futures contract that had $10 000 as the underlying, it had $1000 margin and the Futures contract itself was worth $3. Then I would safe to say that current amount money I can make is $10 000 * $3 = $30 000. Therefore, if the price the price of the stock goes up by $1 then I have effectively made another $10 000$ because $4 * $10 000 = $40 000.
In other words is the current profit/loss of a Futures contract:
P_underlying * P_futures