Penis Girth & Circumference Guide (How to Measure, Averages & Fit)
Girth means circumference: the distance around the shaft, usually measured with a flexible tape around the mid-shaft while erect. The 2015 systematic review reported a mean erect circumference of 11.66 cm (4.59 inches), based on 381 measurements. That is a study average, not a target or a measure of sexual function. For condom sizing, compare your measurement with the nominal width and guidance for the specific product.
Circumference vs diameter: clearing up the confusion
Girth is circumference—the distance all the way around the shaft. Diameter is the straight-line distance across it. For example, a 4.6-inch circumference corresponds to a diameter of about 1.46 inches (3.7 cm). These measurements describe different dimensions and should not be substituted for each other.
How to measure erect girth accurately
Achieve a 100% full erection. Wrap a flexible tailor's tape measure around the mid-shaft (halfway between base and head). Ensure the tape is snug against the skin without squeezing or indenting the tissue. Read the number in inches or centimetres.
Why girth is the key to condom sizing
Circumference is often the most useful starting point when comparing condom widths, but product design, material and length can also affect fit. Check the specific manufacturer’s nominal-width guidance rather than assuming one measurement maps to the same size across every brand.
My Size Report provides a private, calculator-led way to understand measurements against published research. Results are informational and should not be treated as medical advice.