Many men here want to know the size of the average human penis. The aim of this post will be to provide an objective answer. A PubMed search and some Googling turned up several studies in which the penis was measured by medical personnel. In the following list, I will report averages for erect and flaccid stretched measurements. For newbies unfamiliar with the acronyms, please see the glossary. When I do not indicate BP or NBP, this is because the study abstract failed to specify such.

Group 1: Studies specifically aimed at determining average penis size

Study 1 - 80 American men:
NBPEL (100% erection induced by drug injection) = 5.08". FSL = 4.88".
UPDATE (07/18/2005): It appears (from reading another source) that the 5.08" figure is non-bone pressed.

Study 2 - 300 men, "college-aged":
NBPEL = 5.88". EG (midshaft) = 4.97".
17% of men had NBPEL below 4.5" -- and this is out of men who volunteered to be measured by two nurses!

Study 3 - 3,300 Italian men, 17-19 years old:
FSL = 4.92".

Study 4 (added 01/02/2007 - not included in calculations or discussion below) - 271 Jordanian men:
FSL = 5.31".

Group 2: Studies in which average penis size was not the primary goal of investigation (Some guys have expressed concern that doctors fake data in penis-size studies in order to relieve men's insecurities. The following studies should not be prone to this criticism.)

Study 5 - 55 Israeli men, 21-78 years old:
BPEL (100% erection induced by drug injection) = 5.35". EG (base) = 4.29". BPFSL = 4.92".

Study 6 - 111 "younger" (18-19 years old) and 32 "older" (40-68 years old, for whom 100% erection was induced by drug injection) German men:
BPEL (young men) = 5.70". BPEL (older men) = 5.58".
UPDATE (05/13/2007): The full text of the article specifies that these measurements were bone-pressed.

Study 7 - 104 British men, 17-84 years old:
FSL = 5.12".

Study 8 - 123 Korean men, "early 20s" in age:
BPFSL = 4.21". NBPFSL = 3.78".

Study 9 (added 05/27/2005 - not included in calculations or discussion below) - 200 Turkish men, 20-22 years old:
NBPEL = 5.01".

Study 10 (added 05/13/2007 - not included in calculations or discussion below) - 115 Nigerian men, 30-65 years old:
FSL = 5.30". Range: 2.95"-7.68".

Out of these high-quality studies, four included a measurement of erect length, the statistic that most interests men at PE forums. Three of these four included direct injections of a drug into the penis to induce a 100% erection -- so their numbers can't be dismissed as too low due to measurement anxiety. The four studies reported average erect lengths ranging from 5.35" BPEL to 5.88" NBPEL (the latter number comes from college students on spring break in Cancun, who probably had small fat pads). For the three studies that did not include erect measurements, we can estimate that the erect figure would have been about 0.25" longer than the reported stretched flaccid length, judging from the differences in studies that included both FSL and EL. For these three additional studies, the average erect length can be inferred to range from 4.46" BPEL to 5.37" (might be NBP or BP).

Studies in which size is verified by a third party, therefore, have consistently turned up averages below those of self-report studies. For example, the famous Kinsey self-report survey found an average NBPEL of 6.16", while a Durex online survey showed an average of 6.4" NBPEL. In my opinion, to trust men's anonymous self-reports over the data of seven objective medical studies demonstrates penis-size paranoia -- something to which we are prone here. If we look at the objective data instead, the average erect penis length appears to be no greater than 5.5 - 6.5" BP -- and may even be smaller.

Related articles:
» A girl's opinion on size
» Motives for starting PE
» What doctors say about natural penis enlargement?