About

Accurate measurement of thyroid volume is a primary diagnostic step in evaluating goiter, thyroid atrophy, or monitoring response to suppressive therapy. This calculator utilizes the standard ellipsoid formula (Brunn method) applied to both the left and right lobes. The total volume is compared against World Health Organization (WHO) and standard clinical reference ranges to assist in diagnosis. Please note that measuring the isthmus is typically excluded from volume calculations in standard clinical practice.

Formulas

Total Volume V_total is the sum of the volumes of the right and left lobes.

V_lobe = L × W × D × 0.479

V_total = V_right + V_left

The factor 0.479 is the correction factor for the ellipsoid shape of thyroid lobes.

Reference Data

Patient Group	Lower Limit (mL)	Upper Limit (mL)
Adult Women	4.4	18.0
Adult Men	7.7	25.0
Child (6 yrs)	--	~3.5
Child (10 yrs)	--	~6.0
Child (14 yrs)	--	~9.5

Frequently Asked Questions

The Brunn method approximates the thyroid lobe as an ellipsoid. It uses a correction factor of 0.479 (approx pi/6) which is statistically validated to be the most accurate for 2D ultrasound volumetry.

No. The isthmus volume is generally negligible and difficult to measure accurately, so standard protocols sum only the two lobes.

Generally, a total volume exceeding 18 mL in women or 25 mL in men is considered indicative of goiter (thyromegaly), though local iodine-deficiency standards may vary.