What is the average erect penile girth reported in peer-reviewed studies in the United States?

1. What peer‑reviewed studies actually report: pooled estimates vs single studies

Large syntheses and individual clinical samples give slightly different but consistent results. A systematic review and meta‑analysis that pooled thousands of measurements reported an erect penile circumference (girth) mean of 11.91 cm (SE 0.18) from 5,168 measurements aggregated across studies (reported in the 2024 review) ^[1]. A focused U.S. sample of 1,661 sexually active men who self‑measured to obtain appropriately sized condoms reported a mean erect circumference of 12.23 cm ^[2]. Both figures are peer‑reviewed and overlap, placing “average” girth at about 11.7–12.3 cm ^{[1] [2]}.

2. How measurement methods change the numbers

Measurement technique matters. Systematic reviewers distinguished clinician‑measured data from self‑reported measures; clinical measures tend to be more reliable. The pooled meta‑analytic value (11.91 cm) reflects a mix of clinical studies with standardized methods across countries ^[1]. The U.S. study relied on motivated self‑measurement in a research context (men measured themselves to obtain custom condom sizing), which the authors note produced values consistent with other research but still carries self‑measurement bias risks ^[2].

3. U.S.‑specific data vs global aggregates

Available sources do report U.S. results: the 1,661‑participant U.S. sample found 12.23 cm mean erect circumference ^[2]. The 2024 global meta‑analysis also calculated regional differences and lists American measurements as larger for some length outcomes, but the pooled erect‑girth estimate cited (11.91 cm) is a multi‑study aggregate rather than a U.S.‑only mean ^[1]. Sources do not provide a single, definitive U.S. national average beyond that 1,661‑person sample; broader pooled estimates remain useful context ^{[2] [1]}.

4. Variation, percentiles and what “average” means

The literature emphasizes spread as well as mean: studies routinely report percentile ranges for length and girth, showing substantial individual variation ^[3]. Meta‑analyses aggregate means across heterogeneous populations and methods; standard errors (SE 0.18 for the 11.91 cm pooled girth) indicate sampling precision but not all sources give full percentile tables in the snippets provided ^[1]. The 2015 review and news coverage reported an erect girth around 11.66 cm as another widely cited metric, in line with the numbers above ^{[4] [3]}.

5. Sources, limitations and potential agendas

The numbers above come from peer‑reviewed studies and systematic reviews summarized in accessible outlets; the 2024 systematic review/meta‑analysis (which reports 11.91 cm) and the 2015 U.S. condom study (12.23 cm) are the most directly relevant peer‑reviewed findings available in the supplied sources ^{[1] [2]}. Limitations are explicit in those sources: measurement heterogeneity (clinician vs self‑measure), volunteer bias (men who volunteer for size studies may differ), and regional sampling differences all affect means ^{[1] [2]}. Commercial or aggregator sites may adjust or harmonize data for rankings—those adjustments introduce methodological choices and implicit agendas not seen in the primary clinical reports ^{[5] [6]}.

6. Bottom line for readers

If you ask “what is the average erect penile girth reported in peer‑reviewed studies in the United States?” — the best directly reported U.S. figure in these sources is 12.23 cm from a 1,661‑participant study ^[2]. Broad pooled, peer‑reviewed meta‑analytic estimates spanning multiple countries center around ≈11.9 cm ^[1]. Both figures place average erect girth at roughly 11.7–12.3 cm (4.6–4.8 in) in the peer‑reviewed literature available in these sources ^{[1] [2]}.