Measurement of the circumference is the most commonly employed method for evaluating extremity lymphedema. However, comparison between different patients is difficult with this measurement. To resolve this problem, we have formulated a new index, upper extremity lymphedema (UEL) index, which can be easily obtained from measurements of the body. We evaluated correlation between UEL index and clinical stage in patients with UEL. The UEL indices were significantly correlated with clinical stages and could be used as a severity scale. The lower extremity lymphedema index makes objective assessment of the severity of lymphedema through a numerical rating, regardless of the body type. This numerical rating makes the index useful for evaluation of lymphedema severities between different cases.