Normal Testicular Volume in Adult Males
The normal volume of a testicle in adult males ranges from 12 to 25 ml, with an average of approximately 15-20 ml. 1, 2
Measurement Methods and Normal Values
- Testicular volume can be measured using three common methods: Prader orchidometer, ruler measurements, or ultrasound 3
- Ultrasound is considered the most accurate method but is more expensive and less practical for routine clinical assessment 3, 4
- The Prader orchidometer is recommended for clinical practice due to its simplicity, availability, and cost-effectiveness 1, 3
- Mean testicular volume in fertile adult males is approximately 22.5 ml, while infertile men tend to have smaller volumes (median 15.0 ml) 2
- Testicular volumes less than 12 ml are generally considered small or atrophic and may warrant further investigation 5, 1
Clinical Significance of Testicular Volume
- Testicular volume strongly correlates with spermatogenic function and fertility potential 1, 2
- Volumes below 12 ml are associated with:
- Volumes above 25 ml (macro-orchidism) may be associated with certain genetic disorders 6
- Testicular volume positively correlates with total testosterone levels, sperm concentration, and progressive sperm motility in infertile men 2
Age-Related Changes
- Testicular volume increases significantly during puberty, with intensive growth starting around age 10 4
- In adolescents (16.5-18 years), testicular volumes typically range from 6-22 ml 7
- Adult testicular volume stabilizes between 15-25 ml in healthy men 2, 6
Clinical Implications
- Small testicular size (<12 ml) may warrant further investigation, especially when associated with:
- Routine contralateral biopsy should be considered in patients with testicular cancer if testicular volume is <12 ml, especially in those under 30 years of age 5
- The European Association of Urology guidelines note that patients with testicular volume <12 ml have a >34% risk of intratubular germ cell neoplasia in the contralateral testis 5