The definition given by the American Association of Cost Engineering (AACE) is as follows: "the area of engineering practice where engineering judgment and experience are used in the application of scientific principles and techniques to the problems of cost estimation and cost control" .

Cost Engineering is exercised throughout the entire life cycle of the Projects:
 

• during the Initial Evaluation phase;

• in the Conceptual Design phase;

• in the detailed design phase;

• under Construction.

Cost Estimating and Cost Control represent the two basic disciplines on which Cost Engineering is founded.