Average size of penis

Expansion on erection the average increase in penis length on erection is from 3.4 inches to 5.9 inches click for details

Penis size is of great concern to many men. Some consider having a large penis a mark of masculinity; others are concerned that their penis is too small to satisfy their sexual partners.

Average Sized Penis
Remember, the term "average" is used quite loosely, different sources claim different things. Keep in mind that these are just measurements, if you’re above or below these its ok, they are here for you to get a basic idea of the general size differences.

How to measure your penis?

 How to measure your non-erect penis:

Measure the length along the top surface from where your penis meets your body to the tip of the glans. Retract - roll back - your foreskin so you can see the glans if you're uncircumcised.
Measure the girth around the penis with a piece of string, very carefully, at its thickest point. Then lay the string along a ruler to establish its length.

 How to measure your erect penis:

Measure along the upper surface from the very tip of the glans to the place where the top surface of your erect penis meets your body. You will want to measure the length that is exposed for use, as it were, so don't push into the fatty tissue around the base of the shaft. Uncircumcised men can retract their foreskin.
If your penis bends up or down, or from side to side when it's erect, lay a piece of string along the surface of the skin and measure the string with a ruler.
For the circumference of your penis we require two measurements:
1 Around the biggest part of the head or glans of your penis - this will usually be the rim of the glans
2 And around the thickest part of your penis shaft.
Measure both these sizes with a piece of string wrapped around your penis when your penis is at its fullest erection.
 

Regarding the length of the adult fully erect penis (measured along the top of the penis from the groin to the tip), several studies have been performed. Those studies that relied on self-measurement consistently reported a higher average than those that had staff take the measurements.

An UCSF study by Wessells et.al. published in 1996 found an average of 5.1 inches (13.0 cm). (Measured by staff)
A study by a Brazilian urologist found an average of 5.7 inches (14.5 cm). (Measured by staff)
A German study in 1996 also reported an average of 5.7 inches (14.5 cm). (Measured by staff)
A study conducted by LifeStyles Condoms during 2001 Spring Break in Cancun found an average of 5.9 inches (15.0 cm). (Measured by staff)
A study conducted by the Korean Consumer Protection Board (KCPB) at a college campus found an average of 6.1 inches (15.5 cm).
The longest erect penis on record is around 12 inches (30 cm). The shortest erect penis on record is under 1/2 an inch (1.3 cm), not counting cases where men are born without a penis.

Similarly, regarding the circumference of the adult fully erect penis (with the measurement taken from the midshaft of the penis), several studies have been performed. Just as with length, those studies that relied on self-measurement consistently reported a higher average than those that had staff take the measurements.

An UCSF study by Wessells et.al. published in 1996 found an average of 4.9 inches (12.5 cm). (Measured by staff)
A study by a Brazilian urologist found an average of 4.7 inches (12.0 cm). (Measured by staff)
A study conducted by LifeStyles Condoms during 2001 Spring Break in Cancun found an average of 5.0 inches (12.7 cm). (Measured by staff)
A study conducted by the Korean Consumer Protection Board (KCPB) at a college campus found an average of 5.0 inches.
There is an ongoing government study in India commissioned with the goal of helping reduce the high condom failure rate there.

The flaccid penis is measured when fully stretched, from the belly to the tip, excluding the foreskin. The length of a stretched flaccid penis closely conforms to erect length.

Average stretched penile length at birth is about 4 cm, and 90% of newborn boys will be between 2.4 and 5.5 cm (0.94 and 2.17 inches). Limited growth of the penis occurs between birth and 5 years of age, but very little occurs between 5 years and the onset of puberty. The average size at the beginning of puberty is 6 cm with adult size reached about 5 years later. W.A. Schonfeld published a penis growth curve in 1943.

Regarding the length of the adult flaccid fully stretched penis:

Lee et.al. reported in 1980 an average of 13.3 cm (5.24 inches) with a standard deviation of 1.6 cm (0.63 inches)
Sutherland et al reported in 1996 an average of 12.4 cm (4.9 inches) (std. dev. 2.7cm or about 1 inch) in Caucasian peoples, an average of 14.6 cm (5.7 inches) in blacks, and an average of 5.6 cm (2.2 inches) in Asian peoples. This study neglects to take into account height and weight, which may be the primary indicator of penis size.
The length of the unstretched flaccid penis is no guide to the size of the erect penis; indeed, some men with small flaccid penes may have larger erections than men with larger flaccid penis. When a man with a relatively large flaccid penis has a normal or below average length penis when fully aroused, or when a man with a relatively small flaccid penis has a normal or above average length penis when fully aroused, they are known by the slang terms "showers" and "growers" respectively.

Present environmental conditions play a role in the size of a relaxed flaccid penis, in particular cool temperatures. One general physiological response to cold is decreased circulation of blood to the appendages. As the size of the penis very much relies on blood supply, this results in a decreased flaccid size. The slang term "shrinkage" is sometimes used to describe this phenomenon, and was featured in a famous episode of Seinfeld. As humorist Garrison Keillor once said, "At forty degrees below zero, all men are indeed equal."
 

Expansion on erection the average increase in penis length on erection is from 3.4 inches to 5.9 inches

The average penis size is actually between 5.5 to 6.4 inches in erect length and 4.7 to 5.2 inches in girth.

Racial differences in penis size

There's a common belief that blacks have larger penises than whites, and Asians have smaller average sizes than whites. Its absolutely true.