What percentile is a 6.5‑inch erect penis girth in studies that report full distributions?

1. What the major reviews actually measured and reported

A large systematic review that assembled nomograms from multiple clinically measured samples—Veale et al. (the 2015 review summarized in mainstream reporting)—found pooled mean erect circumference figures in the neighborhood of 11.66 cm (≈4.6 in) and used pooled standard deviations to simulate percentile charts for length and girth; that review and its downstream reporting are the basis for most clinical "percentile" claims about penis size ^{[1] [2] [5]}. Independent large clinical studies and summaries commonly report average erect girth in the roughly 11.5–12.2 cm (4.5–4.8 in) range and describe the population distribution as approximately bell‑shaped, which permits conversion of raw measurements into percentiles when the mean and SD are known ^{[3] [6] [1]}.

2. Where a 6.5‑inch (16.5 cm) girth sits relative to reported distributions

Because the pooled clinical mean for erect circumference is about 11.5–11.7 cm, a 16.5 cm girth is several centimetres above the mean—well outside the central "middle 40%" described in syntheses—and therefore in the extreme upper tail of the distribution ^{[3] [1]}. Published public summaries and popular calculators that translate nomograms into percentiles typically flag sizes above roughly 6 in (length) or circumferences noticeably above 12 cm as uncommon; while most published percentile claims focus on length, the same shape of distribution applies to girth and implies that a 16.5 cm circumference would exceed customary 95th percentile thresholds used in clinical nomograms ^{[7] [5] [3]}.

3. Why an exact percentile cannot be stated with certainty from the supplied reporting

None of the supplied sources publishes a single pooled standard deviation and a direct percentile table for erect girth that yields an exact percentile for 16.5 cm without additional modelling assumptions; Veale et al. produced nomograms from simulations and clinical data (and the LA Times summarized those nomograms), but the snippet excerpts provided here do not include the precise SD or percentile cutoffs for girth to permit a verbatim lookup of 16.5 cm ^{[2] [5]}. Clinical studies also vary by measurement method (staff‑measured vs. self‑reported), by where girth is measured (mid‑shaft vs. base), and by sample composition; those methodological differences produce non‑trivial shifts in means and variances that change percentile placement ^{[1] [4]}.

4. Reasoned estimate, alternatives, and caveats

Given the consensus mean (≈11.5–11.7 cm) and the descriptive ranges reported (middle 40% roughly 10.8–12.1 cm), a girth of 16.5 cm is so far outside that central mass that it is reasonable to classify it as extremely rare—likely above the 95th percentile and plausibly at or above the 99th percentile—yet any numeric claim beyond “very rare” requires the original nomogram data or a stated SD to compute precisely ^{[3] [1] [2]}. Alternative viewpoints exist: websites and calculators that compile heterogeneous datasets sometimes produce slightly different percentile thresholds, and self‑reported samples will inflate means and thus shift percentile cutoffs upward; readers should prefer clinician‑measured nomograms ^{[8] [9] [1]}.

5. Bottom line for interpretation and use

Clinically measured literature places average erect girth near 4.5–4.8 inches (≈11.5–12.2 cm) and treats size as a roughly normal distribution; a 6.5‑inch girth (≈16.5 cm) is far above that average and should be considered extremely uncommon in those clinical samples—above typical 95th percentile cutoffs and plausibly in the ≥99th percentile tail—while any exact percentile statement requires access to the full nomogram or pooled SD from the cited systematic review or primary datasets ^{[1] [2] [3]}.