Background: The right ventricular (RV) area is important for diagnosis and follow-up in patients with various diseases, such as in pulmonary hypertension. Objectives: The aim of this study was to define the reference ranges of the end-diastolic RV area in healthy adults and to assess the determining factors. Methods: In the first part of the study 860 healthy subjects (37.6% female; mean age 28 ± 5.84; 395 endurance athletes, 255 strength athletes and 210 non-athletes) were prospectively assessed. In the second part we performed a pooled analysis of studies published between 1979 and 2014 describing the RV area in healthy subjects (n = 5,248).Statistical analysis included the calculation of reference ranges and the analysis of determining factors. Results: Mean end-diastolic RV areas in 860 healthy subjects were significantly larger in endurance athletes (25.1 ± 2.0 cm2) compared with strength athletes (22.9 ± 1.7 cm2) and non-athletes (16.7 ± 2.0 cm2, p < 0.001). In the synopsis of both data sets, mean end-diastolic RV area was significantly larger in European/American males (17 cm2) compared with females (14 cm2, p < 0.001) and in Asian males (16 cm2) compared with females (13 cm2, p < 0.001). The area increased with body surface area and older age. Conclusion: This is the largest data set to define RV size in healthy adults aged <50 years. RV area was determined by age, gender, body surface area, ethnicity and high-level exercise training. High standard deviations resulted in high values for the upper limit of the reference range, which might therefore not be useful as cut-off values for screening purposes. Gender- and ethnicity-specific reference ranges should be used. Further studies in subjects aged >50 years as well as in children are needed.