The size figures you see online vary wildly — largely because people measure in different ways. Here’s how to measure your penis accurately, using the same approach clinicians use, so you get a result you can actually trust.
What you’ll need
A flexible tape measure works best; if you only have a rigid ruler, use a piece of string and then measure the string. Measure when you are fully erect, as flaccid size varies a great deal with temperature and other factors and isn’t a reliable guide.
How to measure length (the clinical way)
Measure along the top of the penis, from where it meets the pubic bone to the tip. Gently press the ruler in to the pubic bone — this is called bone-pressed erect length and is the standard clinicians use, because it allows for any fat pad at the base. Measuring without pressing to the bone will give a shorter reading, which is why casual measurements often differ.
How to measure girth (circumference)
Wrap the tape (or string) around the thickest part of the shaft while erect — usually the middle — and note the measurement where it meets. Girth can differ slightly between the base and mid-shaft, so measure the same spot each time for consistency.
Tips for an accurate result
- Measure when fully erect, in a warm room.
- Use the same method and the same spot each time you check.
- Don’t press the tape into the tissue for girth — keep it snug, not tight.
- Take the measurement more than once to be sure.
How do I compare?
Once you have your figures, see average penis size and girth in the UK and our guide to what counts as a good girth. Bear in mind there is a wide, normal range.
Worried about your measurements?
If your result is causing you concern, a discreet, factual assessment can put it in context and explain your options if you’d like to make a change.
Frequently asked questions
How do I measure my penis correctly?
Measure erect: length along the top from the pubic bone (pressed in) to the tip, and girth around the thickest part of the shaft with a flexible tape.
What is bone-pressed length?
Length measured with the ruler pressed gently to the pubic bone, which accounts for any fat pad and is the standard clinical method.
Should I measure erect or flaccid?
Erect — flaccid size varies too much with temperature and other factors to be a reliable measure.
My measurement worries me — what should I do?
Most worries turn out to be within the normal range. Book a free phone call, or message us on WhatsApp at +44 7457 404374, for an honest assessment.
References
- Veale D, et al. Am I normal? A systematic review and construction of nomograms for penile dimensions. BJU Int. 2015;115(6):978–986 (measurement methodology).
This article is for educational purposes only and does not constitute personal medical advice. All treatment decisions should follow consultation with a qualified professional.
Reviewed by the Clinical Team at London Andrology · Last reviewed: 2026
