In given article various variants of measurement of reactive energy in the presence of the higher harmonics of voltage and a current in an electric circuits are considered. Algorithms of calculation of the reactive energy, applied in various types of electronic meters are resulted. Dependences of measurements on various components on the fifth and seventh harmonics are constructed. Errors are calculated and their maximum values are presented. The data presented in article can be used in practice at construction of systems of measurement of reactive energy in electric circuits.