What is the normal size of a testicle in milliliters (ml)?

Normal Testicular Volume in Adult Males

Normal testicular volume in adult males ranges from 15 to 25 ml, with volumes below 12 ml considered atrophic and potentially associated with higher risk of testicular pathology. 1

Measurement Methods and Reference Values

Several methods can be used to measure testicular volume:

• Ultrasonography: Provides the most accurate measurement and is recommended when precise volume determination is required 1
• Prader orchidometer: A good surrogate for ultrasound measurements in clinical practice, easier to perform and cost-effective 2
• Ordinary ruler: Simple, available, and low-cost method that correlates well with other measurement techniques 3

Normal Volume Ranges by Population

• General adult male population: 15-25 ml 1
• Vietnamese adult men: Mean volume of 13.64 ± 3.44 ml (left testis: 13.94 ± 3.72 ml; right testis: 13.34 ± 3.61 ml) 4
• In a European study of 444 men: Median right testicular volume was 14.1 ml (range 3.0-31.4 ml) and median left testicular volume was 13.0 ml (range 3.5-35.2 ml) 5

Clinical Significance of Testicular Volume

Indicators of Pathology

• Volumes <12 ml: Considered atrophic 1
• Risk factors: Men with testicular volumes <12 ml and age >30 years have a 34% risk of intratubular germ cell neoplasia in the contralateral testis 1
• Fertility implications: Testicular volume positively correlates with total sperm count, sperm penetration, and normal sperm morphology 5

Anatomical Considerations

• The right testis is typically slightly larger than the left testis 4, 5
• Testicular volume is generally independent of age in adult men (after age 20), but dependent on age for men under 20 years 5
• Men with a history of cryptorchidism typically have smaller testicular volumes (median 10.5 ml) compared to men with normal descent (median 14.1 ml) 5

Evaluation Recommendations

When evaluating testicular volume:

• Consider using ultrasound for precise measurements, especially in cases with large hydrocele, inguinal testis, epididymal enlargement/fibrosis, thickened scrotal skin, or small testes 2
• Pay attention to testicular architecture and structure, as non-homogeneous patterns may indicate testicular dysgenesis related to impaired spermatogenesis 2
• Be aware that men with infertility have a higher risk of testicular cancer compared to fertile men 2
• Volumes <12 ml warrant further evaluation, especially in men >30 years of age 1

Developmental Considerations

• Testicular volume increases significantly during puberty, with intensive growth starting around age 10 6, 7
• Mean volume of neonatal testis is approximately 0.35 ml, increasing 10-fold from 1.36 ml at age 10 to 12.83 ml by age 17 6
• Adult testicular volume is typically reached by late adolescence 7