Ask an Expert: What’s the average testicle size?

What is the “normal” when it comes to testicle size? Just as testicular volume varies between men, it varies a bit between the left and right testis.


What is “normal” when it comes to testicle size?


Since testes (or testicles) are ovoid-shaped (a bit like an egg), they are measured by volume, in millilitres (ml).

Testicular volume is related to a person’s height and weight and varies according to race, nutrition, geography, health and environmental factors, so there is a range of what’s normal. About 80% of men have testicular volumes somewhere between 20-30 ml[1]. But just like measuring anything, testicular volume depends on what you use to measure it, and on when and in whom it is measured.

You might have noticed a string of egg-shaped beads of different sizes in your GP’s office. It’s likely an orchidometer, for measuring testicular volume. The person doing the measuring gently stretches the scrotum to hold one testis for comparison to the size of the beads of the orchidometer. The volume of each of the beads is written on them, so when you find one that matches the testis size, you get an accurate and reliable measurement. Both testes can be measured easily, without any physical discomfort, in a couple of minutes.

Before puberty, testicular volume measured by orchidometer is usually less than 3 ml. Testicular volume above 3 ml is a sign that puberty has begun, and as puberty continues, testicular volume rises rapidly. By around 20 years of age, the testes are about as big as they’ll ever be. Testicular volume might decrease a little with age after about 50[2] but there’s not much of a decline until about 80[3]. If your testes are 4ml or less after puberty — around the size of a grape — you should chat to your doctor as small testes are a common symptom of Klinefelter syndrome.

More precise measurement of testis volume can be obtained using ultrasound. This might be used by a fertility specialist, as part of a more detailed ultrasound examination of what’s in your scrotum if you and your partner are having trouble conceiving. The average testicular volume for an adult human, measured by ultrasound is about 14 ml (smaller than measurements made by orchidometer).

Just as testicular volume varies between men, it varies a bit between the left and right testis. You might have noticed that yourself, especially if you’re performing regular testicular self-examinations.

A/Prof Tim Moss

Tim Moss

Biomedical research scientist

Associate Professor Tim Moss has PhD in physiology and more than 20 years’ experience as a biomedical research scientist. Tim stepped away from his successful academic career at the end of 2019, to apply his skills in turning complicated scientific and medical knowledge into information that all people can use to improve their health and wellbeing. Tim has written for and Scientific American’s Observations blog, which is far more interesting than his authorship of over 150 academic publications. He has studied science communication at the Alan Alda Centre for Communicating Science in New York, and at the Department of Biological Engineering Communication Lab at MIT in Boston.


Testicle size
Testicular volume

Did you find this page helpful?

Information provided on this website is not a substitute for medical advice

Call 000 for emergency services

If you or someone you know needs urgent medical attention.

Call MensLine Australia on 1300 78 99 78 for 24/7 support

MensLine Australia is a telephone and online counselling service for men with emotional health and relationship concerns.

Sign up to our newsletter

We release two monthly newsletters – one written for men, family and friends, and another for health practitioners.

Your preferred mailing list

Your name

Your email

Stay up to date


Healthy Male acknowledges the traditional owners of the land. We pay our respects to elders past, present and future. We are committed to providing respectful, inclusive services and work environments where all individuals feel accepted, safe, affirmed and celebrated.


Healthy Male is funded by the Australian Government Department of Health and Aged Care. This website does not host any form of advertisement. Information provided on this website is not a substitute for medical advice.

Trusted information partner of