The difficulty in estimating accurately the losses due to creep, shrinkage, and relaxation of steel lies in: (a) prediction of coefficients related to the quality of concrete, steel, and environment in which the structure will be kept during the period of loss, (b) the interdependence of the amount of prestress loss produced by the three contributory causes. In practice the designer may recourse to results of tests or to recommended practice for values of creep, shrinkage, and relaxation. Once these values are established, the errors resulting from Item (b) above should be eliminated. This paper is written for this purpose. Using a step-by-step procedure which accounts for elastic and creep recoveries of concrete and the effect of variation in stress level on the relaxation of steel, graphs are prepared for use in practice. The use of these allows economical design by accurate estimate of the loss in prestress without the necessity of performing the computation of the step-by-step procedure. /Author/