How to measure correctly
Consistent technique is what makes a percentile meaningful. Here's exactly how clinical studies do it, so your numbers line up with the research.
What you need
- A rigid ruler (not a flexible tape) for length.
- A flexible tape measure or a strip of paper + ruler for girth.
- Full erection — measurements on a partial erection read short.
- A warm room. Cold temporarily shrinks things.
Length (bone-pressed)
- Stand up. Hold the penis out parallel to the floor.
- Place the ruler on top, at the base.
- Press the ruler gently into the pubic bone, compressing any fat pad, until it stops. Read to the tip. This is the bone-pressed (BPEL) figure research uses.
Bone-pressed vs not
Measuring without pressing in (non-bone-pressed) reads shorter — the difference is roughly the
depth of your pubic fat pad. Our calculator lets you pick which you measured and corrects for it.
Girth (circumference)
- Wrap the tape around the thickest part of the shaft (usually mid-shaft).
- Snug, not tight. Note the number where the tape meets.
- If girth varies a lot along the shaft, measure base, middle and just-below-head and average.
Common mistakes
- Measuring on the underside curve instead of the top — adds length that isn't usable.
- Using a soft tape for length — it follows curves and over-reads.
- Not fully erect, or measuring after exercise/cold.
- Comparing a non-pressed number to bone-pressed research data.