What is the average penis length and girth in the general male population?

1. The headline numbers: what large reviews found

A systematic review and meta-analysis of measurements taken by health professionals—often cited as the most reliable aggregate—reported mean erect length ≈13.12 cm (5.16 in) and mean erect circumference ≈11.66 cm (4.59 in), with flaccid and stretched measures lower or intermediate (flaccid ~9.16 cm; stretched ~13.24 cm) ^{[1] [2]}. Multiple clinical and medical outlets repeat these pooled figures and the underlying large sample (up to ~15,000 measured men) as the current best estimates ^{[3] [2]}.

2. Why different studies give different answers: measurement and reporting bias

Studies that rely on self-reported size almost always give larger averages than those with clinician measurements because men overestimate when reporting themselves; reviews that contrast methods emphasize this reporting bias and recommend relying on measured data ^{[4] [5]}. Measurement technique also changes results: standard practice in clinical studies is to press the ruler into the pubic bone (compressing fat) and measure from bone to glans, not including foreskin, and to measure circumference at base or mid-shaft—small procedural differences produce systematic shifts in averages ^[2].

3. Variation by region, sampling and the limits of available data

Recent meta-analyses that searched major databases through 2024 note substantial heterogeneity across studies and WHO regions and flag a lack of standardized measurement protocols as a key limitation, which could produce regional differences or artificial dispersion in pooled estimates ^[6]. Some sources and non‑clinical summaries cite somewhat larger averages (e.g., surveys or preference studies that estimate U.S. averages near 15 cm), but those often use self-report, perception or selection methods rather than standardized clinical measurement ^{[7] [8]}.

4. Percentiles, pathology and what “micropenis” means

Clinical workframes set definitions relative to the population mean: an erect length around 10 cm sits near the 5th percentile in some pooled analyses—only about 5% of men measure below that—while the clinical diagnosis “micropenis” refers to an erect length roughly 2 standard deviations below mean and is used only when otherwise normal anatomy exists ^{[2] [1]}. These cutoffs are statistical and clinical tools, not moral judgments; they guide evaluation for endocrine or developmental conditions ^[1].

5. Why people care: perception, partners’ preferences and practical implications

Perception of average size runs larger than measured averages—pornography and social misperception are often implicated—while surveys of partner preferences sometimes show idealized sizes above measured means (many women in some studies reported preferred sizes larger than the population average) ^{[4] [9] [7]}. Clinically useful takeaways include fitting condoms to girth (circumference matters for condom fit) and recognizing that anxiety about size is common despite most partners reporting satisfaction ^{[10] [3]}.

6. Bottom line and reporting caveats

The most defensible, measured averages in the peer-reviewed and clinical literature place erect length at about 13.12 cm (≈5.16 in) and erect girth at about 11.66 cm (≈4.59 in), with meaningful variation and methodological caveats: self-report inflates values, measurement technique shifts numbers, and regional heterogeneity plus lack of universal protocol limit precision—readers should treat pooled means as useful central estimates rather than definitive personal yardsticks ^{[1] [2] [6]}.