The article proposes a methodology for calculating the power required to heat the edges of a pipe billet towelding temperature during high-frequency welding of longitudinally welded pipes made from low-carbon and low-alloysteels. Both contact and induction methods of energy supply are considered, and the influence of the distance fromthe inductor (or contacts) to the edge convergence point, as well as the configuration of magnetic cores, on energyconsumption and welding speed is analyzed.The authors introduce power increase coefficients k_P1 (maximum) and k_P2 (minimum), which account for the unevendistribution of surface current density along the edges, including cases of sharp and rounded edges, and the presenceof one or two magnetic cores. A formula is proposed for determining the average coefficient k_P as the half-sum of theextreme values, as well as for calculating the required power P_кр, taking into account the variation of specific poweralong the heating zone.It has been established that the gap between the edges (and, accordingly, the angle of their convergence) significantlyaffects the consumed power. It is shown that placing internal and external magnetic cores allows reducing the power atminimal convergence angles of the edges; however, their effectiveness decreases in the zone of very small gaps