Esthetics is a primary consideration for patients seeking prosthodontic treatment. The alteration of the facial vertical dimension can deteriorate the orofacial harmony. When it is essential to assess dentofacial attractiveness, there is a consensus in the research community that the soft tissue evaluation in digital photographs is much more consistent than the traditional cephalometric analyses. The aim of this study was to compare the lower third of the face with the facial segment (ie, the distance between the outer cantus of the eye and the labial commissural), to verify whether or not there are statistical correlations and significant differences between them. Front-view standardized digital photographs of 84 dentate Brazilian subjects were used to measure all facial segments through an image-processing program. The Student t test showed no significant difference between the left facial segment and the lower third of the face. Pearson's product-moment coefficient showed significant correlations between both facial segments and the lower third of the face. After the regression analysis, two mathematical equations were used to correlate the facial segment to the lower third of the face. The distance between the outer cantus of the eye and the labial commissurae can be a reliable guide to estimate the vertical dimension of the rest position. Moreover, when it is measured on the left side of the face there is a better chance to correctly estimate the appropriate size.