The market economy, businesses are required to pay full costs, given their reduction, which contributes directly to increased profits as the main objective of any enterprise. So the production cost is the most important synthetic indicator characterizing the whole business of manufacturers, the final criterion for determining the economic efficiency. As demonstrated, any consumer cost is associated if the following elements: resource consumption, time, place of consumption, activity and product or service. To that end consumption must be subject to join the process of evaluating, measuring, classification, calculation and ventilation in relation to the structures above. This selection process is called aggregation and cost calculation. It is, therefore, a set of mathematical operations, more or less complex, through which the identification, assessment, grouping, splitting and aggregation of consumer items and structures.