Average Flaccid Penis Size (and Why It Tells You Little)

The average flaccid penis is 9.2 cm (3.6 inches) long with a girth of 9.3 cm (3.7 inches), based on 15,521 men measured by researchers (Veale et al. 2015). But flaccid size is the least reliable measurement there is — it changes with temperature, stress and time of day, and it says surprisingly little about erect size.

Flaccid size is controlled by blood flow and smooth muscle tone, and both react to your environment:

• Cold: Cold water or air makes the tissue contract. Shrinkage of a few centimetres is completely normal.
• Stress and nerves: Adrenaline narrows blood vessels. That's why many men look smaller before a date, in a locker room or at the doctor's.
• Exercise: During intense training, blood is redirected to the muscles.
• Warmth and relaxation: A warm shower or being relaxed usually makes it hang longer.

Comparing yourself flaccid, on a cold day, after a workout, is the worst possible test.

Some men are "growers", who gain a lot of length when erect, others are "showers", who look larger flaccid but grow less. The difference largely evens out when erect: two men who look very different flaccid can be almost the same size erect. That's why the locker room is a poor place to judge where you stand.

Grower or shower? →

Doctors often measure stretched length instead: the flaccid penis gently pulled to its full length, measured from the pubic bone to the tip. In the Veale data, the average stretched length (13.2 cm) is almost identical to the average erect length (13.1 cm), so it's a reasonable estimate if you can't measure erect.

How to measure accurately →

Flaccid tells you little — the number that matters is the erect one. The calculator on the homepage computes your exact erect percentile from the same Veale baseline.