Objective <p>Lymphedema occurs when lymphatic fluid accumulates in the interstitial tissue, necessitating diagnosis, treatment, evaluation, and timely decision-making regarding treatment. The circumferential measurement of limbs is the most common method for measuring edema volume. This study aims to develop and standardize a prediction model to estimate upper extremity lymphedema volume based on circumferential measurements of the limb.</p> Materials and Methods <p>This is a cross-sectional study of all patients with upper extremity lymphedema referred to Pooya Physiotherapy Institute in Tehran from 2009 to 2019. Upper arm volume (measured by water displacement) and upper arm circumference in centimeters along the affected and non-affected arms at seven points (A-G) were extracted and recorded for every patient. Potential predictors of edema volume were investigated using linear regression models.</p> Results <p>A total of 9304 arms were measured. The best-fitting linear model was selected. Model sensitivity in estimating lymphedema volume was 86.5% (95% CI, 85.3–87.6%), and specificity was 78.4% (95% CI, 76.1–80.5%).</p> Conclusion <p>This study found that edema volume can be predicted with acceptable performance using circumferential measurement variables. Therefore, limb volume measurement may serve as a reliable proxy for estimating edema volume in clinical settings.</p>