A non-erect penis usually measures between 8.5cm and 10.5cm (3-4 inches) from tip to base.
The average figure is about 9.5cm (3.75 inches), but this kind of precise measurement is rather valueless. Many factors can cause a temporary shrinkage of two inches or more, for instance cold weather or going swimming, so you needn't worry if you happen to fall short of the average figure.
Of course, it's true that some men have big penises and some have smaller ones, just as some men have small feet and some have big feet, but the measurement is not - repeat not - an index of virility.
Most people think that a tall man will usually have a large penis, but this is not entirely true. The distinguished American researchers Masters and Johnson measured the penile lengths of more than 300 men.
- The largest organ was 14 cm (5.5 inches) in the flaccid state. It belonged to a slim man who was 5' 7" tall (170 cm).
- The smallest penis measured 6cm (2.25 inches). It belonged to a fairly heavily built man of 5' 11" (180cm).
A question of perspective
The trouble is that every man sees his own penis in a foreshortened view. The angle at which you look down inevitably makes your penis seem shorter than it is.
But when you glance at another man's organ, there's no such foreshortening effect, so very often it'll look as though the other guy is slightly better endowed.
A lifetime of comparison of this sort (and virtually every male does a quick mental check on each naked man he sees) can easily make you feel a bit inadequate. But it's important to realise the facts about penis length.