An accurate evaluation of thyroid volume, in patients of all ages, is important for the correct diagnosis of a goiter and for sonographic monitoring of thyroid diseases. It is especially important in pediatrics because the linear measurements of a developing thyroid gland do not correlate well with age, sex, or body composition variables. Diverse methods are used to estimate thyroid size and volume. Sonographic volumetry and visual inspection and palpation are used to evaluate the thyroid. Although thyroid size can be easily assessed on physical examination, due to the superficial location of the gland, palpation has low sensitivity and specificity for the management and diagnosis of thyroid disorders. Therefore, thyroid volume measured sonographically is more accurate than thyroid size assessed with a physical examination. Imprecise calculation of thyroid size and volume may lead to false-positive or false-negative diagnoses of thyromegaly, which may result in unnecessary or delayed care.