The average volume of semen produced at ejaculation is 2 to 5ml. Volumes consistently less than 1.5ml (hypospermia) or more than 5.5ml (hyperspermia) are probably abnormal. Lower volumes may occur after very frequent ejaculation and higher volumes are seen after prolonged abstinence.

The World Health Organisation provides a definition of a 'normal' sperm count:

the concentration of spermatozoa should be at least 20 million per ml.
the total volume of semen should be at least 2ml.
the total number of spermatozoa in the ejaculate should be at least 40 million.
at least 75 per cent of the spermatozoa should be alive (it is normal for up to 25 per cent to be dead).
at least 30 per cent of the spermatozoa should be of normal shape and form.
at least 25 per cent of the spermatozoa should be swimming with rapid forward movement.
at least 50 per cent of the spermatozoa should be swimming forward, even if only sluggishly.