An average-sized penis measures roughly 3.5 inches (about 9 cm) long when soft and between 5.1 and 6 inches (13 to 15 cm) when erect. The girth of an average erect penis is about 4.5 inches around. But “average” covers a wide range of shapes, colors, and textures, and most men fall somewhere within a broad window of normal rather than hitting one exact number.
Average Length and Girth by the Numbers
A meta-analysis of 75 studies covering over 55,000 men, published in The World Journal of Men’s Health, found an average erect length of about 6 inches (roughly 15 cm). Earlier large-scale studies placed the average slightly lower, around 5.3 inches erect. The difference comes down to how measurements were taken, when the studies were conducted, and who participated. Stanford researchers noted that average erect length appears to have increased by about 24% over the past three decades, from around 4.8 inches to 6 inches, though the reasons aren’t fully understood.
For context, about 68% of men measure between 4.6 and 6.0 inches when erect. Only about 2.5% are longer than 6.9 inches, and about 2.5% are shorter than 3.7 inches. So if you fall anywhere in that middle range, you’re solidly within normal territory.
Average flaccid (soft) girth is about 3.7 inches, expanding to roughly 4.5 inches when erect. Flaccid size is a poor predictor of erect size. Some men who appear smaller when soft grow significantly during an erection (“growers”), while others stay closer to the same size (“showers”).
Typical Shape and Structure
The penis has two main visible parts: the shaft and the glans (the head). Most penises are roughly cylindrical, often with a head that’s slightly wider or more pronounced than the shaft. Beyond that basic structure, there’s enormous variation in what’s considered normal.
Some penises are wider at the base and taper toward the tip, giving a subtle cone shape. Others have a narrower shaft with a proportionally larger head. Many are relatively uniform in width from base to tip. All of these are common.
Men who were circumcised as infants have the glans permanently exposed, giving the head a more visible, defined look. Men who are uncircumcised have a foreskin that partially or fully covers the glans when soft and typically retracts during an erection. Both are normal, and roughly half of men in the United States are circumcised.
Curvature Is Normal
A perfectly straight erection is only one of many common shapes. Many penises curve slightly upward, downward, or to one side when erect. A mild curve of up to about 20 degrees in any direction is typical and doesn’t indicate a problem. Think of a slight banana shape, either curving up, down, or sideways.
More pronounced curvature (generally over 30 degrees), especially if it develops later in life or causes pain, can be a sign of Peyronie’s disease, a condition involving scar tissue buildup inside the penis. This becomes more common in the 50s and 60s. A curve that’s been present since puberty and doesn’t cause discomfort is almost always just your anatomy.
Color, Skin, and Texture
The skin of the penis is often a different shade than the rest of your body, regardless of your overall skin tone. Rising testosterone levels over your lifetime tend to darken the skin in the genital area, giving it a brown or grayish hue compared to surrounding skin. During an erection, increased blood flow can make the penis appear reddish or even purple, especially at the head. Some men also have freckles or subtle variations in pigmentation along the shaft.
Veins are visible on many penises, particularly during erection when blood flow increases. Some men have very prominent veins, while others have a smoother appearance. Both are normal and largely determined by genetics and body fat levels. Small bumps near the base of the glans (called pearly penile papules) are also common and harmless, appearing in roughly 15 to 25% of men.
Hair typically grows around the base of the penis and on the scrotum. Some men have a few stray hairs on the shaft itself. The amount varies widely from person to person.
How to Measure Accurately
If you want to compare yourself to the averages, it helps to measure the way researchers do. Use a ruler or measuring tape while fully erect. Place the ruler on top of the penis, pressing the end into the pubic bone at the base to push past any fat pad. Measure in a straight line to the tip of the glans. If your penis curves, a flexible measuring tape along the top surface gives a more accurate reading than a rigid ruler. For girth, wrap a measuring tape around the thickest part of the shaft.
The Gap Between Perception and Reality
Men consistently underestimate how they compare. In a large survey published in Psychology of Men & Masculinity, 45% of men said they were dissatisfied with their penis size, while only 15% of women reported being unsatisfied with their partner’s size. Even among men who rated themselves as average, nearly half said they wished they were larger.
Pornography is a major driver of this distortion. Most men understand that performers are selected for being well above average, but persistent exposure still shifts what feels “normal.” The result is a perception gap: men overestimate what average looks like and underestimate their own size by comparison. In reality, two-thirds of men rated their own penis as average, which lines up well with the statistical distribution.
How Appearance Changes With Age
Starting around your 40s, declining testosterone and reduced blood flow gradually change how the penis looks and functions. The head may become a lighter shade as blood flow slows. Pubic hair thins and eventually turns gray or white. The scrotum loses elasticity and hangs lower.
Some men notice their penis appears shorter with age. This can be partly real, caused by reduced blood flow from conditions like high blood pressure or clogged arteries, and partly an illusion created by weight gain around the lower abdomen. Fat deposits at the base of the penis can hide an inch or more of visible length without any actual change in size.
Sensitivity also decreases over time, meaning arousal and erections may take longer. By age 70, roughly 70% of men experience some difficulty getting or maintaining an erection. These are gradual changes that happen over decades, not sudden shifts.