Background In recent years, objective quantitative evaluations have become particularly important. Both qualitative and quantitative evaluations are also available for edema. It is thought that the technical problem of quantitative evaluation can be solved by using a simple and reproducible method. Several studies have evaluated various methods for measuring edema. Limitations, such as weaknesses, measurement complexity, and errors, have been identified. Therefore, this study aimed to consider a simple and effective measurement method for the quantitative evaluation of edema. Methods This study was a prospective, observational study. The subjects were 15 healthy adults (2 male and 13 female). Measurements were performed on the subjects' right lower leg once in the morning and once in the afternoon, with a minimum interval of 4 hours. Results The actual volume of the lower leg was correlated with all indices except the ultrasonic echo findings for subcutaneous tissue. The intra-subject and inter-subject reliabilities for the indices using digital images were very high. The lower leg volume was greater significantly in the afternoon from the morning. Conclusion The leg circumference was measured by utilizing a tape, while the width and volume were measured by utilizing digital imaging suitable for quantitatively evaluating edema. Furthermore, swelling of the lower leg with time can occur in the absence of daily exercise.