Semen typically exits the penis at roughly 18–28 miles per hour (about 30–45 km/h) at the very first “spurt,” but this can also be much slower and sometimes just dribbles out instead.

Quick Scoop

  • The first jet of semen during ejaculation has been measured at around 18 km/h (about 11 mph) in older lab data, while several sexual‑health and popular medical sources commonly quote figures closer to 28 mph for the initial spurt.
  • After that first strong contraction, later spurts are weaker and slower, and in many men the semen simply flows out with gravity rather than “shooting.”
  • Speed and force vary a lot from person to person and even from one ejaculation to the next, depending on things like arousal level, muscle contractions in the pelvic floor, how long it has been since the last ejaculation, and the thickness of the semen.

How it works in the body

  • Ejaculation happens in rhythmic contractions of the pelvic muscles and urethra, usually 10–15 pulses over a few seconds, which push semen out of the penis in one or several spurts.
  • The first or second contraction typically releases the largest amount of semen (often around 40% of the total), and this is when it comes out the fastest; subsequent contractions slow down.

In everyday terms

  • Some men see one strong “shot,” some see several shorter spurts, and others mainly see a dribble; all of these patterns can be normal as long as there is no pain, blood, or sudden unexplained change.
  • If someone notices a big change in their ejaculation (for example, suddenly no fluid at all, severe pain, or blood in semen), it is a good idea to speak with a healthcare professional or sexual‑health clinic. Information gathered from public forums or data available on the internet and portrayed here.