One of the contrator's most challenging responsibilities is the construction estimate. But just what is an estimate? In brief, it is a calculation that takes in all the quantities and costs of the various items and services going into a construction job. But the construction estimate represents much more than a cold calculation. A sound estimate draws the total picture of all the work that is to be done and of all the problems that a builder must anticipant in fulfilling his contract. There are two methods of devising an estimate are the unit- quantity method and the total-quantity method. In the unit-quantity method the estimator calculates the costs for one unit of the project. The estimator then would multiply this unit cost by the total number of cubic yards that are to go into the completed project. To figure a total-quantity estimate the estimator computes the total costs of each separate category or phase of an operation. He tallies separately the costs of materials, labor, equipment and overhead. He then adds the individual costs of these components to get a total for the entire job. Whatever his method, all estimates deal with the five major breakdown: materials, labor, equipment, overhead and profit.