We explore the effect of the band energy on the total energy convergence of metals with respect to k-point density in density functional theory (DFT) calculations. Our tests reveal that traditional approaches, namely band smearing and the linear tetrahedron method, fail to improve the efficiency of metals. This is due to their inability to accurately compute the band energy, which we explain in detail.  We present a numerical algorithm that efficiently computes the band energy and observe more than an order of magnitude reduction in the number of reduced k-points. Our method should significantly increase the computational efficiency of metals in DFT.