Both men and (to a lesser extent, according to studies) women are curious about the average size of men's genitals. However, studies show that the average penis size is both smaller and more uniform from country to country than many people believe. A male’s penis size is primarily determined by genetics rather than geography. Studies also show that proper nutrition during younger years and adolescence is also important in healthy development. Although a few studies have attempted to show a correlation between overall body size (particularly height) and penis length, the correlations have proven negligible. Studies have also disproven the lingering myths that penis size can be determined by the size of one’s shoe, hands, or fingers.
Creating a definitive list of average penis sizes across many countries is a daunting task for two main reasons. First, because creating a worldwide data set typically involves combining the data from many smaller-scale, regional studies that may or may not have had the same parameters. Secondly, because many studies of erect penis length rely upon self-reported data, which is notoriously unreliable, rather than more stringent and precise laboratory measurements. Therefore, while the data listed below is the best currently available, it should still be taken with a grain of salt. The worldwide average length of an erect penis is 13.58 centimeters (cm) or 5.35 inches. Broken down by country, the largest average size was 17.61 centimeters (6.93 inches), found in Ecuador and the smallest was 10.01 centimeters (3.95 inches) in Cambodia. The average penis size in Ecuador also has the largest percentage of body height at 10.54%.