How to measure bicep girth.
Bicep girth is the circumference of the upper arm at its thickest point. Athletes track it to monitor hypertrophy from resistance training; the difference between relaxed and flexed bicep girth indicates muscle quality and peak contractile ability.
Convert Bicep measurement
Typical range: 30–45 cm for trained men, 25–35 cm for trained women
How to measure
Stand with your arm hanging relaxed at your side. Locate the midpoint between the acromion (top of the shoulder) and the olecranon (tip of the elbow). Wrap a flexible tape measure around this point perpendicular to the long axis of the arm. The tape should sit flat against the skin without compressing tissue. For flexed bicep girth, raise the arm to 90° and contract the bicep fully before measuring at the peak of the muscle.
Tips for accuracy
- Measure both arms — most people have a dominant side that's slightly larger
- Record relaxed and flexed values; the difference indicates muscle quality
- Take two readings within 0.5 cm and average them
- Measure at the same time of day, ideally morning before training
What it's used for
Hypertrophy tracking, bodybuilding progress, McCallum ideal-proportions calculation