Many studies have investigated the roles that area and number play in visual quantity estimation. Yet, recent work has shown that perceived area is not equal to true, mathematical area. This simple fact calls into question many findings in numerical cognition and suggests a new theoretical perspective: that area estimation plays a dominant role in visual quantity estimation. We examine two ‘case studies’: (1) a ‘general magnitude’ account of visual quantity estimation, which posits bi-directional influences between area and number. In contrast with prior work, controlling for perceived area reveals a unidirectional relation between area and number (Experiments 1 and 2), and (2) acuity of area and number estimation (Experiment 3). We show how an understanding of the perception of area forces a reevaluation of several findings concerning the relative acuity of number and area estimation. Combined, and in contrast to many prior studies, our findings suggest a dominant role of area in visual quantity estimation.