Implicit cost is considered as the opportunity cost which is involved in the usage of firms own resource. If capital input is not used by the firm in production but is used in the other project, then the loss incurred by the firm for not using that resource will be considered as opportunity cost. These opportunity cost are hard to be quantified by the firm. The average total cost is per unit cost of the factor inputs. The firms only include the economic or accounting cost which is also called explicit cost. These costs show the direct expenditure of the firm on the resources used in the process of production for producing each individual unit of output. Explicit costs are wages paid, salaries, depreciated, expenditure on raw material and so on. So, this can be concluded that average total cost of the firm does not include the implicit cost.