Under the double effect of competition and demand's diversification, companies need today to become more aware of costs. Formed as a result of production development and competitive economy, managerial accounting was found in a constantly evolving which can be evidenced by its very name. In the past appear as the industrial accounting, cost accounting or management accounting, but today is seen most often under the name of "managerial accounting". Any manager- for running a business- needs such a tool enabling it to shape the future, to transform it from an uncertain and risky, in one forecasted, planned with uncertainty and risk understood and measured in financial terms. With these tools, they certainly will take the decisions that will be more grounded and will have much more chance of success in the competitive environment.This is because, in the opinion of the authors, piloting a company based on decisions from a better understanding of internal and external factors would influence activity in a better way. Moreover, this book - by the conclusions of which will fall after detailed analysis of how managerial accounting and cost calculation in a company.