A summing algorithm is proposed in the present paper in which the sum of the partial powers, calculated for the assumption of the independent operation of each oscillator, is used as a first approximation, and the refinements, associated with taking account of the mutual effect of the oscillators, reduce to a refinement of these partial powers. It is convenient to explain the essence of the proposed algorithm by means of a simple equivalent circuit. The proposed algorithm is suitable for use in those special but very common situations at microwave frequencies when it is convenient to deal directly with the powers of the sources being summed, the mutual influence of which leads to the need to solve self-consistent problems. In this case the proposed method can be extended not only to electronic vacuum tubes but also to other microwave devices, in the description of which self-consistency problems arise and to which a discrete solution is applicable, including many solid-state multielement oscillators and amplifiers.