How is profit calculated?

How is profit calculated?
Profit is a positive value for revenue minus costs. (A negative difference is a loss.)

The easiest and most basic way is to take the total revenue of the business and minus the total cost of the business. Hence, Profit = TR - TC. From my understanding, this simple equation have different interpretations based on different subjects. The total revenue or TR, is calculated from the price of a good multiplied with the quantity of good sold. While the total cost, or TC, is the sum of fixed cost and variable cost incurred. Hence, now the equation becomes . . . Profit = P.Q - ( Fixed Cost + Variable Cost ). This equation can change further, depending on what discipline you are looking from. If you are looking from the Economics perspectives, the total cost should be included with the opportunity cost. While from the Accounting perspectives, the opportunity cost is ignored.