Average Penis Size: 2015 & 2025 Study Data

The 2015 review reported mean erect length of 13.12 cm from 692 measurements and mean erect circumference of 11.66 cm from 381 measurements. A 2025 review reported 13.84 cm from 5,669 erect-length measurements and 11.91 cm from 5,168 erect-circumference measurements. These are study averages, not a required size or a personal prediction.

The research behind the numbers

The review included studies in which health professionals measured participants using standard procedures. The overall sample across measurement categories was 15,521, but erect length and erect circumference were available for 692 and 381 men respectively.

The 2025 systematic review

Mostafaei and colleagues published a systematic review in 2025 covering 33 studies and 36,883 participants. The pooled mean erect length was 13.84 cm (5.45 inches), based on 5,669 erect-length measurements. Mean erect circumference was 11.91 cm (4.69 inches), based on 5,168 erect-circumference measurements. The overall review sample is not the same as the smaller samples contributing to each erect measurement.

Why the two reviews report different averages

The reviews include different sets of studies, participant groups and measurement protocols. The difference between their pooled averages should not be interpreted as proof that average size has increased over time. The 2025 review searched studies published up to February 2024.

How to interpret these figures

An average is not a percentile distribution. My Size Report uses its stated 2015 reference distribution for its current percentile estimates and presents the 2025 pooled averages as additional context. A mean value by itself is not enough to generate an updated percentile model.

What is considered the normal range?

The studies provide reference estimates rather than a universal boundary between normal and abnormal. Individual variation is expected, and measurements alone cannot determine sexual function or fertility.

Why popular culture inflates the average

Media examples are not representative samples and are a poor basis for estimating population averages. Published research and consistent measurement methods are more useful points of comparison.

My Size Report provides a private, calculator-led way to understand measurements against published research. Results are informational and should not be treated as medical advice.