When measuring the girth of your penis, should you always use the measurement of the thickest part, as in the base of the penis?
Executive summary
Most clinical guides and doctors’ websites recommend measuring penis girth by wrapping a flexible tape or non-stretch string once around the erect shaft at its thickest point (commonly mid‑shaft or base) because girth is defined as circumference and the widest circumference is the metric most relevant to condom fit and sexual function [1] [2] [3]. There is no single universal rule forced on all contexts—some research protocols measure girth specifically at the base for consistency in studies [4]—so the practical answer is: use the thickest part for everyday/condom purposes, but follow the precise location specified by whichever clinical or research standard is in play [5] [4].
1. Why “thickest part” is the de facto practical standard
Consumer health guides and urology‑oriented sources uniformly instruct users to wrap a soft, non‑stretch tape or string around the thickest part of the erect shaft to get girth—the point where the tape meets is the circumference—because that measurement directly governs condom sizing and many real‑world concerns about fit and comfort [1] [2] [6]. Multiple sources explicitly state “thickest part” or “widest point” as the target site, noting that this is what condom manufacturers and sexual‑health recommendations rely on [7] [8] [9].
2. Where clinical research sometimes diverges: base vs. mid‑shaft
Academic measurement protocols and some clinical studies have chosen a standardized location—often the base of the penis—to reduce variability between observers and improve reproducibility in research datasets; for example, several andrology studies used a disposable tape at the base when reporting girth in a controlled environment [4]. That standardization explains why a paper or clinic might instruct “measure at the base” even though for day‑to‑day concerns many practitioners say “measure at the thickest part” [4] [10].
3. Sources of measurement error to watch for
Experts warn that girth readings can be skewed by stretchy tapes, pulling the tape too tight, fluctuations in temperature and arousal state, and inconsistent measurement sites, so using a non‑stretching flexible tape or string, measuring erect, and avoiding excessive tension are repeated recommendations [7] [11] [5]. Several guides also advise taking three measurements at different times and averaging the results to account for natural variability in blood flow and temperature [12] [5].
4. How to reconcile “base” instructions with “thickest part” advice
For most personal uses—condom selection, comparing against published averages, or tracking changes—wrap the tape around the widest part of the erect shaft and record that circumference; that matches the consumer and clinician guidance found across mainstream health sources [1] [2]. For enrollment in a study, clinical procedures, or surgical planning, follow the exact protocol the study or clinician specifies (for example, bone‑pressed length and base girth), because reproducibility requires a fixed anatomical landmark rather than a variable “widest point” [4] [10].
5. Clear recommendation and practical steps
Measure girth on a full erection, use a flexible non‑stretch tape or a string, wrap gently once around the thickest part of the shaft (commonly mid‑shaft or base), take multiple readings at different times, and average them; if a clinician or researcher asks for a base measurement, follow that instruction for comparability [1] [5] [12] [4]. Be mindful that different sources report slightly different averages and methodologies, so the most useful practice is consistency in technique and alignment with the purpose of the measurement—personal fit vs. clinical research [13] [3].