How to read this calculator
Enter three positive dimensions for one lobe or for both, in cm or mm; the unit applies to both lobes. One complete lobe gives that lobe’s volume. Two complete lobes also give their total. Complete or clear any partly entered lobe before a result is shown.
How the volume is calculated
By default, each lobe is estimated as π/6 × length × width × depth, with dimensions in cm and volume in mL. The WHO method uses 0.479 and defines thyroid volume as the sum of both lobe estimates, excluding the isthmus (WHO/UNICEF/ICCIDD 2007, Annex 2). With π/6 selected, this calculator sums the two geometric lobe estimates and also excludes the isthmus. WHO describes its 0.479 method in a guide for population monitoring of iodine deficiency. In a cadaver ultrasound study, Brunn et al. derived a correction factor of 0.479 against displacement measurements; for identical dimensions, π/6 gives approximately 9.3% higher values. Brunn measured 50 lobes from 25 cadavers and reported an average lobe-measurement error of 16% in that study. The authors studied only slightly or moderately enlarged thyroid glands and cautioned that three dimensions per lobe may be insufficient for large nodular goitres with irregular shapes.
How to measure
WHO’s method uses minimal transducer pressure to avoid distorting the gland anatomy. On a transverse image, measure the maximal depth (anteroposterior) at 90 degrees to the skin surface and the maximal width (mediolateral) at 90 degrees to the depth. On a longitudinal image, measure the maximal length (craniocaudal). Exclude the capsule and the isthmus. If the lobe is longer than the transducer, measure its length in two scans to an internal landmark, preferably, or an external landmark, and sum the measurements.
Reference values
This calculator applies no thyroid reference range. WHO’s 2007 guide tabulates sex-specific 97th percentiles of thyroid volume by age and body surface area for iodine-sufficient children aged 6–12 years, for goitre screening in population monitoring, and states that they apply only if thyroid volume is determined by its standardized method. The values come from Zimmermann et al. 2004, a study of 3529 children aged 6–12 years in areas of long-term iodine sufficiency.
Ellipsoid option
The WHO method uses 0.479; the ellipsoid option uses exact π/6.
The ellipsoid option uses π/6 × L × W × D for each lobe, as in the Thyroid lobe preset of the Ellipsoid organ volume calculator.
Worked example
In a published case of Graves’ disease, ultrasound gave a right lobe of 39.6 × 38.3 × 54.3 mm and a left lobe of 32.8 × 37.4 × 50.6 mm (Mora Moreno 2026). With 0.479 these give 39.45 mL and 29.73 mL, total 69.18 mL. The authors did not state a volume.
| Item | Value |
|---|---|
| Right lobe: Dimension 1 | 39.6 mm |
| Right lobe: Dimension 2 | 38.3 mm |
| Right lobe: Dimension 3 | 54.3 mm |
| Left lobe: Dimension 1 | 32.8 mm |
| Left lobe: Dimension 2 | 37.4 mm |
| Left lobe: Dimension 3 | 50.6 mm |
| Right lobe | 39.45 mL |
| Left lobe | 29.73 mL |
| Total thyroid volume | 69.18 mL |
| Formula | 0.479 × L × W × D |
No thyroid reference range is applied. The isthmus is not included; see How the volume is calculated.
Frequently asked questions
How is thyroid volume calculated from ultrasound?
By default this calculator estimates each lobe as π/6 × length × width × depth, with dimensions in cm and volume in mL; the WHO method uses 0.479. For either selection, this calculator sums both lobe estimates and excludes the isthmus. See How the volume is calculated.
Is the isthmus included in thyroid volume?
No. In the WHO method the volume of the isthmus is not included. See How the volume is calculated.
What is the difference between π/6 and 0.479?
See How the volume is calculated for the Brunn correction factor and the π/6 comparison.
What is a normal thyroid volume?
This calculator applies no reference range. See Reference values.
References
- World Health Organization, UNICEF, ICCIDD. Assessment of iodine deficiency disorders and monitoring their elimination: a guide for programme managers. 3rd ed. Geneva: World Health Organization; 2007. https://iris.who.int/handle/10665/43781
- Brunn J, Block U, Ruf G, Bos I, Kunze WP, Scriba PC. Volumetrie der Schilddrüsenlappen mittels Real-time-Sonographie. Dtsch Med Wochenschr. 1981;106(41):1338–1340. doi:10.1055/s-2008-1070506. PMID 7274082.
- Zimmermann MB, Hess SY, Molinari L, et al. New reference values for thyroid volume by ultrasound in iodine-sufficient schoolchildren: a World Health Organization/Nutrition for Health and Development Iodine Deficiency Study Group Report. Am J Clin Nutr. 2004;79(2):231–237. doi:10.1093/ajcn/79.2.231. PMID 14749228. Abstract-based review.
- Mora Moreno HE, et al. Total Thyroidectomy for Severe Thyrotoxicosis in a Young Woman: A Case Report. Cureus. 2026;18:e107104. doi:10.7759/cureus.107104.
- AlSayed AH, et al. Thyroid Hemiagenesis: A Longitudinal Case Report of Dynamic Thyroid Function. Cureus. 2025;17:e97418. doi:10.7759/cureus.97418. PMID 41431505.