Bicep size is a long-standing fascination in fitness culture, often serving as a visible metric of strength and dedication. While the term “big” is subjective, bicep circumference is a standardized metric used to track muscle development and physique progress. Comparing your measurement to population averages and athletic benchmarks helps quantify what a “big” bicep truly means.
Proper Technique for Bicep Measurement
Accurate bicep measurement requires a flexible measuring tape and consistency. For the relaxed measurement, locate the midpoint of the upper arm, halfway between the acromion process (shoulder tip) and the olecranon process (elbow tip). The arm should hang loosely at the side, not flexed, with the tape wrapped snugly around the circumference at this midpoint.
To measure the flexed circumference, raise the arm horizontally and bend the elbow to 90 degrees, fully contracting the bicep. Wrap the tape around the largest circumference of the muscle belly, ensuring it passes over the highest peak. Avoid pulling the tape too tightly or leaving it too loose. For accurate tracking, consistently use the same method—relaxed or fully flexed—each time you measure.
Average Bicep Sizes Across the Population
Establishing the baseline of the general, non-athletic population helps define what constitutes a big bicep. Health studies typically use the relaxed upper arm circumference, which includes both muscle and fat tissue.
For young adult men (aged 20 to 30), the average relaxed bicep size falls within the range of 13 to 15 inches. This measurement tends to be slightly higher, around 13 to 14 inches, for middle-aged men before declining in older adults.
The average circumference for young adult women is generally smaller, ranging from 12 to 13 inches. Middle-aged women often show a relaxed circumference between 11 and 12 inches. A person’s body mass index (BMI) significantly influences these numbers, as higher body fat contributes to a larger overall arm circumference, even with modest muscle mass.
Benchmarks for a “Big” Bicep Measurement
The size considered “big” depends heavily on the individual’s frame and training level. For a man of average height, a relaxed bicep circumference exceeding 15 inches or a flexed measurement over 16 inches is often substantial. For women, a flexed measurement surpassing 13 inches is typically seen as well-developed and larger than average.
Fit and Lean Individuals
For someone who is considered fit and lean, a 16-to-17-inch flexed bicep clearly signals regular strength training and noticeable muscularity. Arms in the 16-to-18-inch range are described as strong, requiring consistent effort and a relatively low body fat percentage for muscle definition to show through.
Athletic and Bodybuilding Benchmarks
The definition shifts further for those in the athletic and competitive bodybuilding spheres. The “elite” benchmark for men is often cited as the 18-to-20-inch range, representing a high level of muscle mass accumulation. These measurements are common among serious strength athletes and amateur bodybuilders. Professional male bodybuilders often possess arm circumferences reaching or exceeding 20 inches.
The Role of Height and Leanness
Height is a factor in determining how impressive a given bicep measurement appears. A 15-inch arm on a person who is 5’5″ will look significantly more massive than the same 15-inch arm on a person who is 6’5″. Taller individuals require a larger circumference to achieve the same visual impact due to their longer arm bones. For a taller person, a bicep measurement of 17 or 18 inches may be necessary to look as muscular as a 15-to-16-inch arm on a shorter person. The visual perception of size is also influenced by leanness, as a lower body fat percentage provides greater muscle definition.