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Yoxly Awesome Contributors

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Medically Reviewed by:

Dr Danae Maragouthakis

Index finger to thumb? Comparing it to your shoe size? If these ways of measuring your penis ring any bells, well, good news — you’re not alone.

Though these methods may be convenient, let’s explore some more accurate ways to measure penis length and girth and dispel a few myths.

Why Measure Your Penis?

Let’s start with the basics: why would you measure your penis, anyway? 

The majority of men measure their penis out of simple curiosity. However, it’s also good to know your size to make sure you’re buying condoms that are the best fit for you. A condom that’s too big can fall off, and a condom that’s too small can be uncomfortable or more likely to break. Both situations can increase the risk of pregnancy or STI transmission, so it’s important to get it right.

Fortunately, there’s a condom size for every penis, and individual manufacturers often have a guide to help you select the right size condom for you. 

Another thing to point out is that your penis size can actually vary from one day to the next, depending on things like mood, temperature, arousal level, and if you’ve had an erection or ejaculated recently. 

How To Measure Your Penis

So, at what state should you measure your penis, and how do you measure your penis? 

It's commonly assumed that penis size is measured solely when erect, but there's another metric worth considering: SPL, or stretched penile length. This measurement is the distance from the pubic bone to the tip of the flaccid penis when stretched to a maximum comfortable length. SPL is important as it is the primary metric used in scientific studies and literature concerning penile size and correlates well with erect length. 

How to Measure: Stretched Penile Length (SPL)

When measuring your stretched penile length, make sure to be standing in an upright position, and to have a ruler or tape measure handy. 

  • Extend your flaccid penis to a maximum comfortable length
  • Place your measuring tape or ruler at the root of the penis (the base/pubic bone) on the dorsal (front-facing or top) side of your penis. This is important because, if measured from underneath, the measurement may not be accurate. Make sure that any hair or pre-pubic fat is pushed aside so that your ruler is as close to the bone as possible. 
  • Continue to measure in a straight line along your penis. 
  • Stop measuring at the tip of your penis. Note this is a measurement of your stretched penis, not your stretched foreskin. The foreskin (if you have one) can often stretch much further than the tip of the penis.

Take a look at the measuring tape — that’s your stretched penile length! 

How to Measure: An Erect Penis

If you would like to measure your erect penile length, the same process is followed: 

  • With an erection, begin by positioning the measuring tape or ruler at the base of the penis (where it meets the pubic bone). Clear any hair or pre-pubic fat to allow the ruler to be as close to the pubic bone as possible.
  • Proceed to measure in a straight line along the top side of the penis until reaching the tip. This endpoint marks your erect penis length. 

Whether you measure your SPL or erect length is a matter of personal preference, but one important note: your erect length is one of the measurements usually needed when sizing a condom. 

How to Measure Penis Girth

That’s not all! We still have to tackle a second penile measurement: girth. 

The girth of one’s penis is essentially the circumference or “thickness”. When conducting this measurement, you do it the same way for both a flaccid or erect penis. The measurement will be different for each measurement.

  • Use a soft measuring tape and simply wrap it around the thickest part of the shaft, which will most likely be at the base or mid-shaft. 
  • Ensure the tape is laying flat around the penis and is not pulled tight. This is your penis girth.

If you don’t have a soft measuring tape, you can use a piece of string with no stretch. Wrap this gently around your penis, marking the string where it meets itself. You can then measure this length of string with a ruler to find your penile girth.


measuring penis graphic

Is Your Penis Size Normal?

You may be comparing your size to your own expectations, studies, friends, or other sociocultural factors. So let's talk about penis size.

Facts About Penis Size

Researchers often refrain from relying on self-reported measurements when investigating penis size. This is because self-reported measurements have been shown to be inflated — up to an inch larger than when researchers perform the measurement themselves. 

A systematic review looking at 20 different papers on penis size, both erect and stretched, gathered data on penile measurement based on over 15,000 penises. These studies indicate that stretched penile length correlates pretty well with erect length, and that average girth increased with an erection:

  • The average stretched flaccid length was 13.24 cm (5.21 in.) and average erect length was 13.12 cm (5.17 in.).
  • 95% of men had a stretched penile length of between approximately 9.5 cm (3.74 in.) and 17 cm (6.69 in.).
  • The average flaccid girth was 9.31 cm (3.67 in.), and the average erect girth was 11.66 cm (4.59 in.).

It’s worth noting that conclusions from clinical studies may still overestimate average penis size, as men with larger penises may feel more comfortable participating in a study where their penis is measured than those with smaller penises.

What Is a Micropenis?

The medical definition of micropenis is a penis which is <2.5 standard deviations below the average — in other words, a penis that’s smaller than the average penis size. In the above study, a micropenis was a stretched penile length of less than 8.5 cm (3.35 in.).

Penis Size Myths

Let’s debunk some myths: Although larger penis sizes are often assumed to be a sign of masculinity and sexual prowess, this simply isn’t the case. Penis size is not related to sexual satisfaction, masculinity, attractiveness, or fertility

Media portrayals and pornography are key culprits in these perceptions, and they play pivotal roles in shaping men's self-esteem. But it’s important to realise that both media and pornography frequently exaggerate the size of male genitalia through actor selection and filming techniques. Contrary to the societal emphasis on size, research indicates that women prefer an average-sized penis, and 84% of women are perfectly satisfied with the size of their partner’s penis.

Medical Conditions Can Affect Penis Size

Various medical conditions can affect both the actual and apparent size of the penis, too. This includes issues like:

  • Obesity, which can obscure penile length due to excess fat around the pubic area 
  • Peyronie's disease, in which fibrous scar tissue causes penile curvature and potential shrinkage 
  • Hormonal imbalances, such as hypogonadism
  • Genetic conditions, such as Klinefelter syndrome

Wrapping It Up

This has been a lot of information about penises. Let’s sum up some key takeaways: 

  1. Properly measuring your penis is important for practising safe sex and choosing the right size condom.

  2. The common metric for penile size in studies is stretched penile length, while most men refer to their erect length. Both are legitimate ways to measure your penis.

  3. Myths and misconceptions surrounding penis size are common (especially thanks to porn and media), so don’t believe everything you hear! 

  4. People with a range of penis sizes can be healthy, normal, fertile, and have satisfying sex live

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Yoxly's Awesome Contributors (YACs) are a diverse group of individuals who are passionate about public health, and committed to furthering our mission. Yoxly provides a platform where a variety of sexual health topics (some more awkward than others!) can be explored, in an informative and non-judgmental way. If you'd like to become one of Yoxly's Awesome Contributors, contact us!