We analyze the band occupations to assess the extent of band overlap (nesting) near the Fermi level. In a typical semiconductor with a well-defined band gap, bands below the Fermi level are fully occupied (valence bands) and those above are unoccupied (conduction bands) at 0 K (DFT calculation). In this case, there are no partially occupied bands. In contrast, a metal is characterized by overlapping bands with partial occupancies at numerous k-points around the Fermi level. We therefore evaluate the fraction of partially-occupied k-points relative to the total number of sampled k-points. If this fraction is small, it is possible that the material is a narrow-gap semiconductor or semimetal, but less likely to be a true metal. Specifically, we calculate the ratio,