We provide guidelines of penile length and circumference to assist in counseling patients considering penile augmentation.

Materials and Methods:

We prospectively measured flaccid and erect penile dimensions in 80 physically normal men before and after pharmacological erection.


Mean flaccid length was 8.8 cm., stretched length 12.4 cm. and erect length 12.9 cm. Neither patient age nor size of the flaccid penis accurately predicted erectile length. Stretched length most closely correlated with erect length.


Only men with a flaccid length of less than 4 cm., or a stretched or erect length of less than 7.5 cm. should be considered candidates for penile lengthening.


  • 1 : Elongation of the penis. Chung Hua Cheng Hsing Shao Shang Wai Ko Tsa Chih1990; 6: 17. Google Scholar
  • 2 : Harnrohrencapacitat und Tripperspritzen. Munch. Med. Wochenschr.1899; 46: 1016. Google Scholar
  • 3 : Normal growth and variation in the male genitalia from birth to maturity. J. Urol.1942; 48: 759. LinkGoogle Scholar
  • 4 : Human Sexual Response. Boston: Little, Brown & Co.1966. Google Scholar
  • 5 : Penis size increase between flaccid and erect state: an analysis of the Kinsey data. J. Sex Res.1988; 24: 177. Google Scholar
  • 6 : Clinical study of the longitudinal deformation of the flaccid penis and of its variations with aging. Eur. Urol.1992; 21: 284. Google Scholar
  • 7 : Caucasian penis: what is the normal size?. J. Urol., part 21994; 151: 323A. abstract 381. Google Scholar
  • 8 : Sonographic measurement of penile erectile volume. J. Clin. Ultrasound1992; 20: 247. Google Scholar
  • 9 : Determination of erectile penile volume by ultrasonography. J. Urol.1989; 141: 1123. LinkGoogle Scholar
  • 10 : Fetal phallic growth and penile standards for newborn male infants. J. Ped.1975; 86: 395. Google Scholar
  • 11 : Penile extensibility: to what is it related?. J. Urol.1992; 148: 1432. AbstractGoogle Scholar
  • 12 : The elasticity and the tensile strength of the tunica albuginea of the corpora cavernosa. J. Urol.1990; 143: 642. AbstractGoogle Scholar
  • 13 : The effects of aging, diabetes and vascular ischemia on the biochemical composition of collagen found in the corpora and tunica of potent and impotent men. Int. J. Impotence Res.1990; 2: 75. Google Scholar
  • 14 : Sexual Behavior in the Human Male. Philadelphia: W. B. Saunders Co.1948. Google Scholar
  • 15 : Complications of penile lengthening and augmentation seen at 1 referral center. J. Urol.1996; 155: 1617. LinkGoogle Scholar

From the Department of Urology, University of California School of Medicine and San Francisco General Hospital, San Francisco, California.