The aim of this study was to assess the dimensions of the septal cartilage available for grafting in patients undergoing open rhinoplasty and analyze whether the size of the external nose might be a useful indicator of the size and amount of harvestable septal cartilage. A prospective study was conducted on 55 Korean rhinoplasties. Intraoperative measurement of the harvested septal cartilage with preservation of 10 mm width l-strut was performed. The correlation between the quantity and size of the septal cartilage in situ with anthropometric measurements were evaluated. The mean caudal length of the harvested septal cartilage was 15.1 mm, the mean dorsal length was 18.2 mm, and the mean area was 520.9 mm2. Only 5 patients (9.1%) had cartilage sufficient for full-length dorsal onlay grafts, whereas 10 patients (18.2%) had septal cartilages of length >25 mm that could be used as spreader grafts. Dimensions of the septal cartilage in situ did not correlate with preoperative external nose measurements. The amount of harvested septal cartilage is usually insufficient for simultaneous use for multiple grafts in Korean. External nose size may not be a useful indicator of the availability of adequate septal cartilage for rhinoplasty. The need to harvest additional graft material should be kept in mind during preoperative planning for rhinoplasty procedures.