Purpose: The aim of this study is to determine whether a difference in the amount of bone graft material is needed between edentulous patients and dentulous patients and to calculate the amount of augmentation for a sinus lift procedure. Methods: 19 patients(20 sinuses) were included to measure maxillary sinus volume. Facial CT scanning was performed using MX 8000 IDT CT devices(Philips, USA). And it was used for IDLvm(The IDL Virtual Machine) 6.0, CT Volume Analyzer Ver 2.3 program to measure maxillary sinus volumes Results: At edentulous patients, volumes(mean${pm}SD$) of the inferior portion of the sinuses were $0.56{pm}0.13cm^3$(5mm height), $2.35{pm}0.57cm^3$(10mm height), $4.85{pm}1.10cm^3$(15mm height). At dentulous patients, volumes(mean${pm}SD$) of the inferior portion of the sinuses were $0.41{pm}0.18cm^3$(5mm height), $1.76{pm}0.42cm^3$(10mm height), $3.80{pm}0.84cm^3$ (15mm height). A significant correlation was found between augmentation height(5mm, 10mm, 15mm) and the calculated sinus volume.(p=0.027, p=0.018, p=0.044) Conclusions: A significant correlation was found between augmentation height(5mm, 10mm, 15mm) and the calculated sinus volume. Detailed preoperative knowledge of sinus lift augmentation volume is helpful in determining the appropriate amount of the bone graft material.