Semen volume is measured in millilitres (mL) as part of a semen analysis. It tells you how much fluid your glands produced and delivered, not how many sperm are in it. Fluid from the testicles and epididymis, which carries the sperm, makes up only around a tenth of the total. Roughly 65% comes from the seminal vesicles and about 25% from the prostate2.
The World Health Organization (WHO) builds its reference values from fertile men. In the updated 2021 figures, the lower reference limit for volume, the 5th centile below which only 5% of those fertile men fell, is 1.4 mL1. Earlier WHO guidance used 1.5 mL3, which is why you will still see both numbers quoted online.
Neither figure is a pass mark for fertility. Volume is one of the most changeable results in a semen analysis, and the same man can produce noticeably different amounts from week to week, mostly depending on how long it has been since he last ejaculated. We cover that day-to-day swing in more detail in Is it normal for semen volume to change day to day?
What is a normal semen volume?
Anything at or above 1.4 mL sits within the WHO's current reference range. There is no official upper limit, and a single reading below it is a prompt to repeat the test, not a diagnosis.
Reference limits describe the spread of results in fertile men; they are not a line between fertile and infertile. The WHO data were collected from more than 3,500 men across twelve countries1, and plenty of men below the 5th centile still father children without help.
Labs usually ask for a sample after a set number of days without ejaculating, because volume depends so heavily on that gap. If your result comes back low, the first step is normally a second test under the same conditions.
What changes semen volume?
Time since your last ejaculation has the biggest everyday effect, and volume also drifts down with age. Anything that affects the seminal vesicles, prostate or the ducts between them can lower it too.
Here is what the research supports, and what it does not:
- Abstinence: in a review of the research, 23 of the 24 studies that looked at volume found it rose with longer gaps between ejaculations, and one study found the fastest daily gains in the first four days3.
- Age: a meta-analysis of 90 studies covering 93,839 men found a statistically significant age-related decline in semen volume4.
- Gland output: because the seminal vesicles supply most of the fluid, problems with them, or blockages in the ducts they drain through, can reduce volume noticeably2.
- Collection: a lab result will under-read if any of the sample is lost, so always tell the lab if you missed some.
- Medical causes: a sudden drop can point to retrograde ejaculation or another cause of hypospermia.
Does semen volume affect fertility?
Only indirectly. Volume is the vehicle, but sperm count, movement and shape matter more, and a large volume can still carry few sperm.
Your total sperm count is calculated by multiplying sperm concentration by volume, so volume does feed into it. But because most of the fluid comes from the accessory glands rather than the testicles2, a generous load says little about sperm production on its own.
Talk to a doctor if your volume is consistently very low, if you notice little or nothing coming out at orgasm, if your urine looks cloudy after sex, or if you have been trying for a baby for a year without success.
Can you increase semen volume?
Leaving a longer gap between ejaculations reliably increases the volume of the next one. Beyond that, the options are much less certain.
The abstinence effect is consistent across studies3, but it comes with a trade-off for sperm quality that we explain on the ejaculatory abstinence page. For a practical round-up, read How to increase semen volume: what actually works, and for the evidence on specific products see semen volume supplements.
Common questions
Is 1 mL of semen normal?
It is below the WHO lower reference limit of 1.4 mL, so a lab would flag it. A single low sample often reflects a short gap since your last ejaculation or an incomplete collection, so doctors usually repeat the test before drawing conclusions.
Why is my semen volume lower than it used to be?
Frequent ejaculation is the most common everyday reason, and volume also tends to fall gradually with age. A sudden, lasting drop, a dry orgasm or cloudy urine after sex is worth raising with a GP.
Does a bigger load mean more sperm?
Not necessarily. Most of the fluid comes from the seminal vesicles and prostate, so volume and sperm count are separate measurements. A semen analysis is the only way to know your count.
Read more on this
How to increase semen volume: what actually works
Is it normal for semen volume to change day to day?
Zinc and semen volume: does it actually work?
Sources
- Campbell MJ, Lotti F, Baldi E, et al. Distribution of semen examination results 2020 - A follow up of data collated for the WHO semen analysis manual 2010. Andrology. 2021;9(3):817-822. PubMed
- Anamthathmakula P, Winuthayanon W. Mechanism of semen liquefaction and its potential for a novel non-hormonal contraception. Biol Reprod. 2020;103(2):411-426. PubMed
- Ayad BM, Horst GV, Plessis SSD. Revisiting the relationship between the ejaculatory abstinence period and semen characteristics. Int J Fertil Steril. 2018;11(4):238-246. PubMed
- Johnson SL, Dunleavy J, Gemmell NJ, Nakagawa S. Consistent age-dependent declines in human semen quality: a systematic review and meta-analysis. Ageing Res Rev. 2015;19:22-33. PubMed
Not medical advice. Written by Eric Stephens from the research cited above; not reviewed by a doctor. If something worries you, see a GP.