Studies of breast volume and size have failed to take into account the aesthetic value of the nipple–areola–breast proportion. These data are important to plastic surgeons in planning breast reduction, augmentation, and reconstruction. In the current study, the anatomic size of the nipple, areola, and breast was measured in 37 women aged 20 to 64 years, and their proportions were calculated. The areola–breast and nipple–areola proportions were 1:3.4 and 1:3, respectively. The natural nipple–areola–breast proportion is approximately 1:3. This study provides a general guideline for plastic surgeons for planning breast surgery with optimal aesthetic results.