Since the plate area has been reduced by the presence of the hole, the normal stress acting on the net area is greater than the normal stress acting on the gross cross-sectional area.

${\mathrm{\sigma }}_{\mathrm{net}}=\frac{\mathrm{P}}{{\mathrm{A}}_{\mathrm{net}}}$

Although a uniformly distributed normal stress is shown on the net area, the actual stress is non-uniform, increasing markedly at the hole boundary. Stress concentration factors are used to account for this phenomenon.