The testicles are the primary male reproductive glands responsible for producing sperm and the hormone testosterone. Healthcare professionals typically focus on volume and size as the practical metrics for health assessment. Understanding normal testicular volume is important because changes in size can be indicators of overall reproductive and hormonal health. The size of these organs exists within a predictable range that is tracked throughout a person’s life.
The Typical Weight and Size Range
A healthy adult testicle generally weighs about 15 to 25 grams each. Since direct weighing is impractical, volume measurement in milliliters (mL) is the standard clinical approach. The normal volume for a fully developed adult testicle typically falls between 15 and 25 mL, though a range of 12 to 30 mL is considered healthy.
A normal testicle measures approximately 3.5 to 5.5 centimeters in length and 2 to 3 centimeters in width. It is entirely typical to have a noticeable difference in size between the two testicles. This difference, known as testicular asymmetry, is an expected anatomical variation that does not affect function in most cases.
The right testicle is frequently slightly larger than the left, and the left testicle often hangs lower in the scrotum. This asymmetry is usually not a health concern unless the difference is substantial or accompanied by pain or other symptoms. Regular self-examination helps a person establish what is normal for their own anatomy.
Natural Factors Influencing Testicular Mass
Testicular mass and volume are influenced by several factors. The most significant factor is age. Before puberty, testicular volume is small, typically less than 3 mL.
Growth accelerates significantly with the onset of puberty, continuing until the testicles reach their adult size around age 18. The adult volume is maintained through the continuous processes of spermatogenesis (sperm production) and testosterone secretion.
Hormonal status is closely linked to testicular size. Genetics also plays a role in determining an individual’s final adult size, contributing to the wide range of what is considered normal. While slight size reduction may occur naturally with advanced aging, any sudden or significant shrinkage is typically a sign of an underlying issue.
Methods for Assessing Volume and Weight
Healthcare providers focus on accurately measuring the size of the testicle to estimate its mass. One of the oldest and simplest clinical tools is the Prader orchidometer, which consists of a set of twelve ellipsoid beads of increasing size, ranging from 1 to 25 mL. The examiner compares the patient’s testicle to the beads to find the closest match for a quick, approximate volume measurement.
Although the orchidometer is convenient, studies have shown it tends to overestimate the true testicular volume, especially in smaller sizes. For a more precise measurement, ultrasound imaging is used, which is considered the most accurate method. Ultrasound allows for the measurement of the testicle’s length, width, and height in millimeters.
The volume is then calculated using the modified ellipsoid formula: Length x Width x Height x 0.71. This calculated volume provides a highly reliable metric for monitoring size over time.
Clinical Significance of Weight or Size Changes
Abnormal changes in testicular size or mass are often the first physical signs of a pathological health condition. Testicular atrophy is defined as a significant reduction in size and can be caused by hormonal imbalances that suppress the pituitary gland’s signaling, such as the use of anabolic steroids or testosterone replacement therapy (TRT). Atrophy also commonly results from infections like orchitis, which is inflammation often caused by the mumps virus or bacteria.
Varicoceles, which are enlargements of the veins within the scrotum, can also lead to atrophy by impairing blood flow and damaging the sperm-producing tissue. Untreated testicular torsion, where the spermatic cord twists, rapidly cuts off blood supply and can cause permanent shrinkage and damage if not addressed promptly.
Conversely, enlargement or weight gain can be indicative of other problems. Hydroceles, which are collections of fluid within the membrane surrounding the testicle, can cause significant, non-painful swelling. Acute infections like orchitis initially cause painful swelling and temporary enlargement.
In rare but serious cases, a significant increase in mass, often accompanied by a firm or irregular texture, can be a symptom of testicular cancer. Any sudden, painful, or persistent change in the size, weight, or feel of a testicle warrants a prompt consultation with a healthcare provider.