Overhead constitutes all indirect materials, indirect labor and indirect expenses. Total cost of a cost centre or cost unit has been divided into two categories such as direct cost and indirect cost. All indirect costs are called overheads. These costs can not be conveniently identified with a particular cost centre or cost unit.
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According to I.C.M.A. indirect cost as ” expenditure on labor, material, services which can not be economically identified with a specific salable cost per unit. Overhead costs are known as supplementary cost Indirect cost, on cost etc.