Normal Erection Size

Unfortunately for some men, the concern about the size of their penis can cause significant worry and stress.  Men often do a visual “guestimate” of their penis size.  These “guestimates” are often incorrect because of the vantage point from above.  Online searches often results in over-inflated self-reporting.  Self-reporting is like fish stories – they’re often embellished.  In some cases posted measurements were made by measuring the underside of the penis rather than the backside which adds portions of the penis found beneath the scrotum.  One study[i] on self-reported lengths showed an average of one inch (2.5cm) longer than what controlled trials have found. 

Here we will focus primarily on the size of the erect penis since the size of the flaccid penis varies from moment to moment in men depending on temperature, physical activity, and other issues.  Most men recognize that when it is cold or after physical activity like sports, the flaccid penis is more compacted than at other times.  In fact, observations have been made that flaccid size has little to do with erect size and men who are “smaller than average” when flaccid may be “larger than average” when erect.  A study[ii] of over 15,000 men found that only 55% of men are satisfied with the size (length and width) of their penis.  Another study showed even lower satisfaction rates and found that when surveyed, only 27% of men were “satisfied” with the length of their penis[iii].  For men who are concerned they may be "too small", click HERE; for those who are concerned they may be "too large", click HERE.  In fact, a medical condition called Short Penis Syndrome can leave men preoccupied and distressed about the anatomy of their penis. 


It is rare for a man to have a penis size that is outside of the “normal” sized range even though 45-73% of men are not satisfied with the size of their penis.  Concerns over the size of the penis are perhaps the number one concern in men with Body Dysmorphic Disorder. 

Many men seek “treatment” for a “small penis” online.  Unfortunately, online sources selling penis enhancement products often assert that penis sizes of 18cm (7 inches) or more are normal when in fact less than 1% of men have a penis this large. It is no wonder so many men feel their penis is below average in size if this is what the internet, pornography, and other non-reliable sources on the internet are telling them is “normal”.  Instead, “normal size” is any length greater than 9cm (3.5 inches) – half the size of what many online sources say is “average”.   

Overall a flaccid penis between 3 to 4 inches long or an erect penis between 4 ¾ and 6 ¼ inches is totally normal.  Penis girth (circumference) is often less of a concern for men, but any width (from one side to the other) that is 1 to 1 ½ inches across when flaccid or 1 ½ to 2 inches across when erect is normal as well.  Keeping in mind that men who have been circumcised may have a slightly narrower flaccid penis due to the foreskin being removed and men who have a more oval shaped circumference to their penis may be slightly wider than this and still be considered normal.  And just because a man may be slightly above average for one measurement doesn’t mean he won’t be slightly below average on the other measurement.  Even though there are few differences from one man to the next, each man is unique and may be more slightly below average in length and slightly above average in width or vis versa.[iv][v]  

In summary, size doesn’t matter and should not be a cause for concern unless the size is so far from the normal range as to create physical or sexual issues.  In essence, size really doesn’t matter – men should just feel comfortable in their own skin and with their own unique anatomy.  However, since many men reading this will still want to know where the fall on the "size continuum" there are detailed results from clinical trials below.


The size of the flaccid penis compared to the size of the erect penis are not always correlated.  For example, a man may be slightly above average when flaccid then slightly below average when erect.  So any inadvertent comparisons in a locker room or gym shower based on flaccid penis size are not a good gauge.  Research has suggested that men who are smaller when flaccid actually “grow” more when they get an erection, so that in the end, nearly all men have an erect penis that is about the same size – no matter how big or small they are when flaccid.  This supports the saying that “some men are ‘show-ers’ and some men are ‘growers’.”[vii]

[vii] (12/10/16)


Until recently there have been few reliable studies showing “what was normal” when it came to erection length and how men varied from one another.  Because of this, some researchers set out to find the answers to these questions and create graphs that could be used by healthcare provider to indeed show what is and isn’t normal.  After reviewing 17 different studies involving over 15,000 men – they came up with data that can help establish “what really is normal”. [viii]   Stretching a flaccid penis out as far as it will go almost always is the same length as the penis when it is erect, so many studies measure stretched flaccid lengths rather than erect lengths. 

It is important to recognize that the measurements in these studies were performed by healthcare providers under controlled environments.  Measurements were made from the very base of the penis on the dorsal (back) side from the pubic bone all the way to the tip of the glans.  Some small differences in length between men can be attributed to how much of the penis protrudes outside the body versus inside the body (behind  the scrotum and into the pelvis).

The average length of the erect penis was found to be 13.2cm (5¼ inches) in length (see the image below on this page).

Size - Average.jpg

To put things in perspective, half of men are within ¾ inch (2cm) – between 4¾ and 5 ½ inches (12-14cm) in length as shown below.

Size - 25th & 75th.jpg


The girth (or distance around) the penis has also studied.  The normal girth of the flaccid penis is about 9cm (3 ½ inches).  Most guys would only know that by using a measuring tape.  90% of men were between 7.8 to 10.8cm (3 to 4 ¼ inches) in girth which would correlate to anywhere between 1 and 1¼ inches wide when simply viewed from above.  Keep in mind, this study was performed on men from Europe, so the majority of these men may not have been circumcised – circumcised men may be normally a little smaller “around” because they don’t have the extra foreskin.  The girth of the erect penis was only measured in just over 300 men and similar commonalities were found.  The average girth of the erect penis was 11.6cm (4¾ inches).  90% of men were between 10.5 to 15.8cm in girth (4.1 to 6.2 inches).  This which correlates to 1½ to 2 inches across if a man’s penis is circular.  It is worth noting that a circular circumference of the penis when erect is most common (see below left).  However, some men have a penis that is more oval in shape thus the penis may appear wider from side to side and narrower from top to bottom (see below right).  So even though two men may have the same girth, the width may be different.  This is because some men have a penis that is more circular shaped (lower left), oval (lower right) or somewhere in between (middle).



Below is a chart showing the 5th percentile up to the 95% percentile in erection size (working right from left - 5th, 10th, 25th, 50th, 75th, 90th, 95th percentiles).  

Size - Percentiles.jpg
Size Percentiles.jpg

Since girth is not always associated with length, it is possible for some men to have a narrower or thicker appearing penis.  The following two charts show examples of sizes that are longer and narrower (top) where the percentile for length is greater than the percentile for girth as well as sizes that are shorter and broader (bottom) where the percentile for girth is greater than the percentile for length.

Size - Narrow.jpg
Size - Broad.jpg

Images on this page from top to bottom include:

  1. SvitlanaNiko/ & joshya/ (modified)

  2. SvitlanaNiko/ & joshya/ (modified)

  3. Ellepigrafica/

  4. SvitlanaNiko/ & joshya/ (modified)

  5. Original Table Design

  6. SvitlanaNiko/ & joshya/ (modified)

  7. Original Table Design

  8. SvitlanaNiko/ & joshya/ (modified)

  9. Original Table Design