When it comes to penis size, what matters more to women: length or girth?

Although a number of scientific studies about women’s penis preferences have been published in recent years, surprisingly few of them have addressed this question. The vast majority focus only on how women feel about length, while completely ignoring girth.

This nearly exclusive focus on length is odd because, of the two studies I found that addressed the length vs. girth question, both of them pointed to the same conclusion: girth matters more.

In the first study, published in 2002, researchers in The Netherlands asked 170 sexually active adult women about their penis size preferences. Here’s what they found:

Penis Length Penis Girth
Very Important <1% 2%
Important 20% 31%
Unimportant 55% 49%
Totally Unimportant 22% 18%

As you can see, the majority of women in this study said that both length and girth were unimportant. However, among those who felt that size did matter, girth was rated as more important than length.

In the second study, published in 2006, researchers surveyed 556 sexually active women in Croatia. The results were similar to the earlier findings in that women rated girth as more important than length.

This more recent study also found that women’s penis preferences depended upon how sexually experienced they were.

Specifically, among women who reported 1 to 2 partners total, length and girth were rated pretty similarly in terms of importance. As the number of partners increased, so did the importance placed on both penile dimensions. With more experience, women came to rate girth as being even more important than length.

This suggests that neither dimension of penis size matters that much to women until they’ve established some comparison level. This comparison level seems to have a bigger effect on how women feel about girth, though.

Together, these studies tell us is that some women do indeed care about length, but that more women care about girth. The obvious question many of you are probably wondering at this point is why?

It likely has to do with the fact that women have far more nerve endings surrounding the entrance to the vagina than they do deep inside the vaginal canal. A thicker penis may therefore be desirable because it simply offers more stimulation overall, including some amount of clitoral stimulation.

Another possibility is that penis length is something most women just don’t think that much about because the average vaginal depth is actually shorter than the length of the average penis. Put another way, maybe length isn’t that important to women because most guys are already long enough.

So what do women think is optimal when it comes to penis girth and how does that match up to the average guy?

In a study published last year, women were given a set of life-size penis models and asked to choose which one they would prefer on a partner. The ideal penis chosen for a long-term male partner was 4.8 inches in girth, compared to 5 inches for a casual partner.

These numbers are virtually identical to those obtained in an online study of 1,661 men who measured their own penises with a standardized tool, who reported an average girth of 4.8 inches.

In short, the available data suggest that, when it comes to penis size, girth matters more than length. But most guys will find it reassuring to know that what women think is optimal when it comes to girth seems to be right in line with what’s average.

Justin Lehmiller, PhD is a sex educator and researcher at Ball State University and author of the blog Sex and Psychology. Follow him on Twitter @JustinLehmiller.