This work presents an assessment of the ultimate compressive strength of damaged steel plates with a local dent. Extensive non-linear finite element analyses are performed, where three groups of analyses are considered. In the first group, the effect of the dent orientation (longitudinal and transverse) is studied for three plate thicknesses. For the second group, the direction of the dent depth (upward and downward) with respect to the global initial imperfection is explored. In the third group, the variation of the dent size for several plate thicknesses and its influence on ultimate compressive strength is investigated. The post-collapse behaviours are discussed and the inflection plate slenderness with and without dent is observed, at which the behaviour of the plate changed. A certain dent breadth to the plate breadth ratio is established, revealing the different plate response. Based on the performed analyses, a generalised expression of the ultimate strength reduction factor due to dent is developed.