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Last updated: Dec 03, 2021
3 min read

How to measure your penis the right way

yael cooperman

Medically Reviewed by Yael Cooperman, MD

Written by Michael Martin

Some guys can get… creative when it comes to measuring the size of their penis. It’s tempting to cheat and add an extra inch, especially if you have a touch of penis anxiety. But apparently, there is a right way to measure your penis, and odds are, you’re probably not measuring your penis in the most accurate way. 

Keep reading to find out what science says about how to properly measure your penis length and girth.  


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How to measure penis length

Measuring your penis correctly is simple, but that doesn’t mean everyone knows how to do it. Here’s how to correctly measure the length of your penis:

  1. Start on the top side of your penis (the side of the penis facing up towards you when you look down). 
  2. Put the end of your ruler or measuring tape at the base of the penis, right up against the pubic bone (where the penis meets the body). Be sure to push past any excess fat or pubic hair so the ruler is right up against the bone. 
  3. Measure in a straight line from the pubic bone to the tip of the penis. 

Ta-da! That’s your actual penis length. According to a 2015 study, the average flaccid length is 3.6 inches, while the average length of an erect penis is 5.17 inches (Veale, 2015).

How to measure girth

Penis girth—the circumference of the penis, or how thick it is—gets a lot of attention in the world of men’s sexual health. Here’s how to measure it properly: 

  1. Wrap a flexible tape measure or a piece of string (which you can measure against a ruler after) around the middle of the shaft of the penis.
  2. Any part of the shaft will do, so feel free to find the widest point.

The average flaccid penis girth is 3.67 inches. The average erect penis girth is 4.59 inches (Veale, 2015).

The right way to measure your penis

You may be wondering why you should measure your penis from the top side rather than the bottom side. After all, measuring the top of the penis is a shorter distance than the underside of the penis because it has a clear stopping point—the pubic bone. But because of that clear stopping point, it’s a more reliable measurement. 

When you measure the underside of the penis, you can skew results by measuring into the pudendal area (aka “the taint”). On the other hand, most researchers push measurements into the pubic area as far as they can go—regardless of any hair or belly fat. So your weight and grooming habits won’t alter the accurate measurement of your penis.

It’s important to note that it doesn’t make much difference if your penis is circumcised or uncircumcised. The foreskin doesn’t add much (if any) length to the penis.

Should you measure your penis erect or flaccid?

Either way is fine, so long as you know what you’re measuring and what to expect. There is obviously some difference between erect and flaccid measurements. It can be a little easier to measure erect and typically gives more satisfying numbers, but it’s also important to keep your results in perspective.

Regardless of how you measure, your penis is probably—statistically speaking—big enough. And, whether you have an above-average or small penis, you can have and provide sexual satisfaction and self-confidence. Speak with your urologist or another healthcare provider for medical advice if you’re concerned about your penis or experiencing conditions like erectile dysfunction or premature ejaculation.  


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.


  1. Veale, D., Miles, S., Bramley, S., Muir, G., & Hodsoll, J. (2015). Am I normal? A systematic review and construction of nomograms for flaccid and erect penis length and circumference in up to 15 521 men. BJU International, 115(6), 978–986. doi: 10.1111/bju.13010. Retrieved from 

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.