Kinsey penis size studies started way back in the 1950’s.
If you’re like most men, your own penis size research was first conducted in the showers during middle school…
And you probably drew conclusions from that study which didn’t exactly boost your confidence, right?
From there, your research most likely drew from images in pornography and delicate inquiries put to your more experienced sex partners.
You may have looked up averages online, or followed links to a handful of click bait articles with titles like The Countries With the Largest Penises Are, etc….
Scientists have also studied penis size using various methods, with the first modern research happening in the 1940s. Schonfeld and Beebe used a ruler and some rings to measure the length and girth of 1,500 volunteers.
Their research ran into some problems, but became the foundation of the field.
Then in the 1950s, Dr. Alfred Kinsey conducted the work that remains most referenced to this day. He interviewed nearly 20,000 men and recorded the sizes of thousands of penises.
Since then a variety of studies have been conducted, with varying degrees of good faith and good science behind them.
But for over 50 years now, the Kinsey research is some of the most widely cited and best respected in the field.
Here’s what his research can tell us about our own size and what we can do about it.
Kinsey Penis Size Studies – The Research:
Lack of consistency and standardization was an issue in much of the research predating Kinsey’s landmark study.
For example, some studies measured flaccid length while others measured stretched length.
Some recorded race or nationality, and others did not. Some measured with no attention to room temperature or other environmental conditions.
Just imagine measuring your own penis flaccid while getting out of a warm bath, flaccid after walking in the snow, erect just before sex, and with a semi from watching female beach volleyball.
Which is the real length of your johnson?
Now you understand the importance of standardization.
Kinsey standardized his research by surveying men and giving them exact instructions as to how to measure their members.
He told the men:
- Measure fully erect (thus standardizing the status of the penis, and accounting for much of the difference caused by ambient temperature).
- Measure from belly to tip, along the top of the penis (thus standardizing the definition of “length” for purposes of the study).
He then sent them home with pre-stamped cards to mail back to him with their results. Just over 2,500 cards came in, forming the basis of his results.
Flaccid vs Erect Length
We all understand that there’s a big different between flaccid and erect penis length.
Thankfully, Dr. Kinsey was smart enough to standardize his measurements so his data could be easily compared across subjects.
Dr. Kinsey chose to have his subjects measure their penises while erect.
This probably helped the accuracy of his results, because there’s a much wider range in male penis size while flaccid.
Most flaccid penises range in size from 1-4 inches, but most average erections are about 5-7 inches in length.
In general, smaller flaccid penises get longer than larger flaccid penises when erect.
It makes sense if you think about it – if two penises are the same length erect, the one that’s smaller while flaccid will need to grow more than the larger one in order to achieve the same erect size.
This is the basis for the shower vs grower debate.
For this reason, Kinsey believed that the flaccid size of a man’s penis is not a good indicator of his full erect size.
It’s probably also the main reason he chose to have his subjects report their erect length in his landmark study.
Kinsey Penis Size Studies Problems
Kinsey’s research, though good, had three serious problems. This doesn’t invalidate his findings, but they are worth keeping in mind before we move on to look at what he found:
- It’s a self-reported study. Dr. Kinsey didn’t personally measure how long and thick his subjects’ penises were. He asked them how long they were, and assumed they were telling the truth. Self-reported research is considered suspect, and for good reason, especially when dealing with subjects as emotionally charged as the length of a man’s member.
- It was conducted in the US in the 1950s. This means the reporting would come overwhelmingly from white men of western european descent. More recent research has shown that penis size varies with ethnicity, so the “average” findings cannot necessarily be generalized to all male populations.
- There was no supervision of the research. Kinsey gave specific instructions, but nobody watched to make sure the subjects followed those instructions carefully. Neither did they provide a standard ruler, or check to confirm the participants used similar methods. This makes the findings less reliable.
On the plus side, the sheer size of Kinsey’s reporting sample does a lot to help with numbers one and three.
If a participant fibbed and fudged, or simply made procedural mistakes, the 2,499 other results do a lot to counteract that.
Bottom line: Kinsey’s research provides one set of useful data for comparing men’s penis lengths, but the data isn’t perfect.
Kinsey Penis Size Study – What is “Average?
You’ve probably been reading this whole article looking for the information in this section.
For that matter, this was the purpose of Kinsey’s research, and that of his predecessors. They wanted to determine what “normal” looked like to aid in diagnosis of things that weren’t normal.
Understanding the limitations to Kinsey’s accuracy and findings, let’s look at Kinsey’s Results. All results I list below are based on measurements of fully erect penises (source).
Average length of a penis, as measured along the top from belly to tip, is 5 to 6.5 inches.
Average circumference of a penis, at center, is 4-5 inches.
The doctor gave a range because the results, like most results in studies of this kind, come in as a bell curve. The most common measurements fall in the middle of the range, with fewer results as you reach the smallest and the largest answers.
Without getting into too much math, the range of results is cut into five equal portions. Kinsey reported the “center” set of results as the average.
If your penis measurements fall within these (admittedly broad, as a proportion of the possible sizes) ranges, you are perfectly normal.
Kinsey Penis Size Studies – Conclusion:
Dr. Alfred Kinsey’s research is the most frequently quoted because it remains the broadest survey about penis size ever conducted...and as you remember from high school science, the larger a sample size the more reliable the results.
Use the good doctor’s findings wisely, though.
It can be useful for goal-setting, but don’t let numbers you dislike get you down. Tons of research has found that size only matters if it erodes your confidence (unless you’re significantly above average, in which case it actually hurts).
One final note. Another of Kinsey’s projects investigated how long men thought their penises were.
In 1979, he interviewed 4,000 men and gave them an unmarked ruler, asking each to move his finger along the ruler until he reached what he thought his full erect length was.
Most men stopped a half inch or so short of their actual penis size.
Apparently, most men feel worse about the length of their penises than the size of their actual junk should indicate.
That’s a fact worth keeping in mind.