However, the truth is that penises come in all sizes and there is no 'normal' length for a man's member. But according to the NHS, for adults the average penis size is about 14 to 16cm (5.5 to 6.3 inches) when erect, while the average girth is 12 to 13cm (4.7 to 5.1 inches).
In fact, a penis would only be considered unusually small if it was less than three inches (7.6cm) long when erect. These measurements are based on a review carried out by Professor Kevan Wylie, a consultant in sexual medicine at the University of Sheffield.
"When you look down at your own organ, it seems shorter than it really is," he told the NHS. "In contrast, when you glance around at other guys in changing rooms or showers, you get a sideways view of them. So they usually seem to be longer than you are."
In addition, there is a large variation in the angle of an erect penis, so there is no 'normal' shape. Some erect penises will point straight up, while others seem to aim straight down. What's more, some have a slight bend to the left or right, and this is rarely anything to worry about.
However, if you have a more significant bend in your penis that may cause you pain or makes it hard to have sex, you could be suffering from Peyronie's disease, which is a medical condition that results in thickened area or hard lump (plaque) in the shaft of the penis.
In this case, it is best to have a chat with your GP, as there are a number of treatments that can help resolve the problem and get your sex life back on track.