Average Size of an Erect Penis in America
The average length of an erect penis in America is approximately 5.36 inches (13.61 cm), with a range typically between 5.1 and 5.5 inches (12.95-13.97 cm). Based on the most comprehensive research data, the average erect penis length is likely closer to 5.1 inches (12.95 cm) when accounting for volunteer bias in studies.
Research Findings on Penis Size
Scientifically Measured Data
- According to a review of 10 studies where researchers directly measured erect penises, the combined mean was 5.36 inches (13.61 cm) based on 1,629 men 1
- For stretched penis measurements (which correlate with erect length), the mean across 21 studies was approximately 5.11 inches (12.98 cm) from 13,719 men 1
- A systematic review constructing nomograms from multiple studies found the mean erect length to be 13.12 cm (5.17 inches) with a standard deviation of 1.66 cm 2
Self-Reported Measurements
- In a study of 1,661 American men who self-measured for condom fitting purposes, the mean erect penile length was 14.15 cm (5.57 inches) with a standard deviation of 2.66 cm 3
- The mean erect penile circumference in this same study was 12.23 cm (4.81 inches) with a standard deviation of 2.23 cm 3
Important Considerations
Measurement Methodology
- How a man becomes erect for measurement may influence the dimensions reported 3
- Most men in studies measured their penis while alone using hand stimulation to achieve erection 3
- Clinical measurements tend to be more accurate than self-reported measurements, which often suffer from volunteer bias and social desirability bias 1
Perception vs. Reality
- Most men believe the average erect penis length is greater than 6 inches (15.24 cm), which is a misconception 1
- This misconception is partly due to often-cited studies that relied on self-reported measurements, which tend to overestimate size 1
- Studies show that a majority of men wish they were larger, despite having normal-sized penises 1
Clinical Relevance
- The American Urological Association considers penile lengthening surgeries to be risky, and most men seeking such surgeries actually have normal-sized penises 1
- For context, women's preferences in studies suggest they prefer penises only slightly larger than average for both one-time encounters (16.3 cm/6.4 inches length) and long-term relationships (16.0 cm/6.3 inches length) 4
Normal Range and Variability
The normal range for erect penis length shows considerable variation, typically within 1-2 standard deviations of the mean. This means most men (approximately 95%) fall within the range of about 9.8-16.4 cm (3.86-6.46 inches) when considering the data from systematic reviews 2.
Penis size has been found to have some correlation with height, with studies showing consistent but moderate correlations (r = 0.2 to 0.6) between height and erect or stretched penis length 2.