What do large-scale meta-analyses report as average erect penis length and girth?

1. What the biggest reviews found: clinician-measured averages

Systematic reviews and meta-analyses that pooled measurements taken by health professionals report a consistent picture: a 2015 systematic review reported an average erect length of 13.12 cm (5.17 in) and an erect circumference of 11.66 cm (4.59 in) ^[1]. A more recent, larger meta-analysis that searched through literature up to February 2024 reported an erect length mean (SE) of 13.84 cm and an erect circumference mean (SE) of 11.91 cm based on thousands of measurements (n for erect length = 5,669; n for erect circumference = 5,168) ^[2]. Both analyses measured length from pubic bone to tip while compressing any pre-pubic fat pad and measured girth at base or mid-shaft, which standardizes comparisons ^{[1] [2]}.

2. Why self-reported studies show bigger numbers

Multiple reviews emphasize that studies relying on volunteer self-measurement report significantly higher averages than those in which clinicians measured participants. The 2015 review and subsequent summaries note that volunteer bias and self-measurement inflate means, so clinician-measured studies are generally considered more reliable for population averages ^{[1] [3]}.

3. Range, percentiles, and what “average” covers

Meta-analyses give not just means but percentile ranges: for example, one commonly cited aggregation found median/mean erect length around 5.1–5.5 inches and indicates most men fall within roughly 10–16 cm (3.9–6.3 in) for erection length; the 95th percentile is often reported near 16–16.5 cm (6.3–6.5 in) ^{[3] [4] [5]}. The 2015-derived figures place an erect length of 10 cm (3.94 in) near the 5th percentile and roughly 16.5 cm near the 95th percentile, illustrating substantial within-population variability ^[5].

4. Geographic and methodological heterogeneity

The large 2024 meta-analysis explicitly reports heterogeneity across WHO regions and cautions that averages differ by region and study methods; for instance, stretched and flaccid means were larger in studies from the Americas ^[2]. The authors note considerable dispersion in data and recommend standard measurement protocols to reduce heterogeneity in future research ^[2].

5. Practical measurement tips and clinical definitions used in studies

Studies that aim for accuracy typically measure from the pubic bone (compressing pre-pubic fat) to the tip of the glans and measure girth at mid-shaft or base; flaccid and stretched-length measures are reported separately because flaccid size poorly predicts erect size in some datasets ^{[1] [2]}. Reviews highlight that measurement technique matters a lot when comparing studies ^{[1] [3]}.

6. What the reviews say about perception, bias, and counseling

Reviews note that many men overestimate how large “average” is and that a sizable fraction are dissatisfied with their size despite being within typical ranges; volunteer/self-selection bias and pornography may skew perceptions of what is normal ^{[3] [5]}. Clinical literature recommends counseling and realistic education rather than risky enlargement attempts ^{[6] [3]}.

7. Limits of the current reporting and where uncertainties remain

Although large meta-analyses aggregate thousands of measurements, authors emphasize moderate-to-high heterogeneity, differences in recruitment (volunteers vs. clinic populations), and variation in regional representation; these factors limit how precisely one can generalize a single “global” average ^[2]. Available sources do not mention long-term secular trends with strong, conclusive evidence—some reports suggest small changes over decades but are cautious ^[6].

Bottom line: clinician-measured meta-analyses cluster around about 13–13.8 cm (5.1–5.4 in) for erect length and about 11.7–11.9 cm (4.6–4.7 in) for erect girth, with meaningful spread around those averages and consistent upward bias in self-reported studies ^{[1] [2] [3]}.