“Shower” is a term sometimes used to describe people whose penises are a similar length when they’re soft (flaccid) or hard (erect). “Growers” are people whose penises get significantly longer when erect.

The terms “grower” and “shower” are often used to describe how much longer a person’s penis gets when it’s erect compared to flaccid. Researchers sometimes describe this as the “change ratio.”

The authors of a 2018 study defined the difference between a “grower” and a “shower” as follows:

  • Grower: penis grows much longer when going from being flaccid to being erect
  • Shower: penis doesn’t show any major change when going from flaccid to erect

Although some studies have examined average penile lengths and change ratios, there isn’t a definitive change ratio value to officially categorize people as growers or showers.

Keep reading to learn more about possible classification ratios, how to measure your penis, and more.

Terms to know

  • Flaccid: This is the default state of the penis when you’re not sexually aroused. The penis is soft and hanging loosely from your groin area.
  • Stretched: This occurs when the penis isn’t erect or even sexually aroused, but is elongated from its normal state. This can happen to your penis whether you’re a shower or a grower.
  • Erect: This happens when the penis tissues fill up with blood when you get sexually aroused. The penis stays this way until you ejaculate or until you’re no longer aroused.

The change ratio figures most commonly cited when classifying people as growers or showers are from the 2018 study mentioned above, which included 274 participants who had erectile dysfunction (ED).

Researchers found that the median change in size from flaccid to erect across all the participants, shower or grower, was 4 centimeters (cm) (1.5 inches).

This 1.5-inch figure served as a baseline for whether a participant was a shower or grower. So, a person was a grower if their penis grew more than 1.5 inches when erect and shower if it grew less than 1.5 inches.

However, more recent studies in different parts of the world reported different numbers, which means the baseline for growers or showers could be different. For example:

  • In a 2023 study in 55,761 people with a penis globally, the average flaccid penis length was 8.7 cm (3.4 inches) and erect length 13.9 cm (5.5 inches), suggesting an average change of 5.23 cm (2 inches).
  • In a 2021 study in 14,597 people with a penis in Vietnam, the median flaccid penis length was 9.03 cm (3.5 inches) and stretched length 14.67 cm (5.78 inches), suggesting a median change of 5.64 cm (2.2 inches).
  • In a 2021 study in 4,685 people with a penis in Italy, the average flaccid penis length was 9.47 cm (3.7 inches) and erect length 16.78 cm (6.6 inches), suggesting a median change of 7.31 cm (2.9 inches).

Many factors can influence the different change ratios and what is considered a grower or shower.

Each study may use a different cut-off point, and factors like the number of participants, geographic region, penile measurement techniques, temperature, and arousal state can affect the reported figures.

Several factors can contribute to your penis length when it’s flaccid, stretched, or erect, and how much it lengthens during an erection. These may include:

  • Tissue elasticity: The capacity for your penile tissues to stretch and grow all contribute to how your penis looks. This includes the outer layers of skin, the inner layers of fibrous tissue, and the ligaments that attach the penis to the body at the groin area. Age and genes may influence how elastic your tissues are.
  • Health conditions: Any health condition that affects blood flow, penis arteries, and the nervous system may contribute to how your penis grows when you get erect. This may include ED, heart conditions, obesity, high blood pressure, depression, some cancers, and diabetes, among others.
  • Hormones: Having low levels of testosterone may influence how your penis develops, including its length and girth, and could increase the risk of developing ED.
  • Circumcision: People who are circumcised may have a shorter penis length by 2 millimeters (mm).
  • Collagen: According to a 1992 study, nearly half of the tissue in your penis is collagen, the most abundant protein found throughout your body. Your genetics contribute to your body’s distribution of collagen, too.

According to the 2018 study, out of the 274 reported participants, 26% were growers and 74% were showers. Growers experienced an average 2.1-inch change in length, and the showers had about a 1.2-inch change in length.

The participants in this study were receiving treatment for ED, so some underlying penile function issues may have also contributed to the overall increase in length.

Remember, figures may vary widely depending on geographic location, study type, and measuring techniques, among other factors.

This doesn’t reflect the entire world population, and there isn’t enough data to fully understand which one is more common.

In many cases, you’ll know without doing any tests to determine which group you fall into.

If your penis looks almost exactly the same whether it’s soft or hard, you’re probably a shower. If it looks drastically longer or bigger when it’s erect, you’re probably a grower.

But you can figure it out for sure by following some of the following tips:

  1. While flaccid, measure from the tip of the penis head (glans) to the base of the shaft: Make sure the bottom of the ruler, measuring tape, or whatever you’re using is flush with the skin around the base of the penis to get the most accurate measurement.
  2. Get erect: Do whatever you feel like doing to accomplish this — just don’t do it in public or around someone who did not consent to seeing it.
  3. Measure your penis again from tip to base: If the difference in length is more than 1.5 inches longer than your flaccid measurement, you’re a grower. If the difference is less than 1.5 inches, you’re a shower.

If you’re unable to get erect, you can use the stretched measurement:

  1. While you’re still flaccid, stretch out your penis by slowly pulling outward on the head or the skin around the head (this may be a little more comfortable).
  2. Stop stretching when it starts to feel uncomfortable.
  3. Measure your penis again from head to base.

Yes, changes in tissue elasticity, hormones, blood flow, and collagen may influence how your penis appears when it’s flaccid or how much it grows over time when you get erect.

As you get older, you might become more of a shower as your tissues stretch out.

On the flip side, some people may become more of a grower as their tissues shrink or become less elastic over time. This causes the penis to retract and experience a larger increase in length when you get erect.

How much your penis grows in length when it’s stretched or erect isn’t necessarily associated with overall size.

For instance, the 2018 study found that a grower’s penis may lengthen more from their baseline length. But if the shower’s baseline measurement is much longer, the final measurements when stretched or erect may be similar.

Comparing your erect or stretched penis to average figures may give you a better idea of your overall erection size. Research from 2023 found that the average global penis size when stretched is 12.93 cm (5.1 inches) and 13.93 cm (5.5 inches) when erect.

The use of binary terms such as “male” and “female” or “men” and “women” in this article reflects the language of the sources we’ve used. Unless otherwise noted, it’s unclear whether the research we reference included participants with expansive gender identities.

What matters the most is how you feel about your penis.

If you’re comfortable with your penis and feel confident using it, then how it looks when it’s flaccid won’t make a difference in how satisfying your sex life is.

A 2025 study in 52,031 heterosexual men and women found that 55% of men were not satisfied with their penis size, while 85% of women were satisfied with the penis size of their partner.

Confidence and communication with your partner are crucial to a healthy sex life. These things are more closely associated with having a solid, positive relationship that can then translate into a better, more communicative sexual relationship with that person.

If you feel self-conscious about the size of your penis, consider speaking with a mental health specialist. They can help you identify, understand, and manage negative thought patterns and behaviors to help improve your mental health and quality of life.

The difference between growers and showers isn’t much of a difference at all.

According to limited research, the average change in length between the two is only an inch and a half. And what your penis looks like when it’s flaccid has no bearing on how it looks, feels, and works when it’s erect.

What matters is that you like your penis and you’re happy with it. Talk with a doctor or other healthcare professional if you’re concerned about your penis health.