Body Frame Size Calculator

Estimate body frame size — small, medium, or large — from height and wrist circumference using the height-to-wrist ratio method.

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Sex

Units

Height (cm) Wrist circumference (cm)

Measure around the wrist just below the wrist bone (distal end of the radius).

Medium frame Medium

Medium

Frame size

9.72

Height / wrist ratio

Frame	Ratio threshold (male)
Small	> 10.4
Medium	9.6–10.4
Large	< 9.6

What frame size tells you Medium frame — average bone structure. Standard ideal weight and body composition reference ranges apply. Body frame size reflects skeletal structure and is often used alongside ideal body weight formulas to adjust for bone density. It is an estimate — bone structure is influenced by genetics, ethnicity, and individual variation.

Body Metrics

Body Frame Size Calculator

This calculator estimates your body frame size — small, medium, or large — using the height-to-wrist circumference ratio, a method used in nutritional assessment and ideal body weight estimation.

About this calculator

Reviewed March 2025

Methodology

Height-to-wrist ratio: r = height (cm) / wrist circumference (cm). Thresholds: male small r > 10.4, medium 9.6–10.4, large < 9.6; female small r > 11.0, medium 10.1–11.0, large < 10.1. Based on Grant JP et al. (1981) Surgical Clinics of North America.

Limitations

Wrist circumference is influenced by body weight and soft tissue, not just bone structure; the ratio is an estimate rather than a direct skeletal measurement.
Thresholds are derived from older, primarily Western population data and may not generalise across all ethnic groups.

Disclaimer

This calculator is for informational purposes only and is not a substitute for professional body composition assessment.

Sources

Grant JP et al. — Current techniques of nutritional assessment, Surg Clin North Am 1981

See our calculation methodology and editorial standards for how this estimate is produced.

What is body frame size?

Body frame size is a classification of skeletal structure that reflects bone density, width, and overall skeletal robustness. A person with a large frame has denser, wider bones relative to their height; a small frame individual has lighter bone structure. Frame size affects how much lean mass and body weight a person can 'healthily' carry.

Frame size classification is used alongside height and sex in ideal body weight formulas (such as Hamwi, Devine, and Robinson) to adjust reference weights upward for larger frames and downward for smaller frames.

How frame size is measured

Two common methods exist: wrist circumference measurement and elbow breadth measurement. This calculator uses the height-to-wrist circumference ratio (r = height / wrist in cm). For men: small r > 10.4, medium r 9.6–10.4, large r < 9.6. For women: small r > 11.0, medium r 10.1–11.0, large r < 10.1.

The wrist circumference method is practical and requires only a tape measure. Wrist circumference reflects bony prominence with minimal soft tissue contribution, making it a reliable proxy for skeletal frame. Measure just below the wrist bone (distal radius).

Frame size and ideal weight

The Hamwi formula (1964) for estimating ideal body weight incorporates frame size: baseline weight plus or minus 10% for large or small frame. For example, a 175 cm man has a Hamwi baseline of approximately 72 kg; a large frame adjusts this upward to 79 kg, a small frame downward to 65 kg.

Frame size adjustment is a rough correction rather than a precise individualisation. It captures some of the variation in skeletal mass that BMI and simple height-weight tables do not account for, but it is one factor among many in body composition assessment.

Frequently asked questions

How do I measure my wrist correctly?

Measure the circumference of your wrist just below the wrist bone — at the narrowest point between the wrist joint and the hand. Use a flexible tape measure and keep it snug but not tight. Measure your non-dominant wrist if possible.

Does frame size affect my target weight?

Frame size is used in some ideal body weight formulas to adjust the target weight by roughly 10% in either direction. However, most modern body composition guidance focuses on body fat percentage and lean mass rather than frame-adjusted ideal weight, as these are more directly linked to health outcomes.

Can frame size change over time?

Bone structure is largely fixed in adulthood, so frame size classification does not change significantly after skeletal maturity. However, small differences in wrist girth due to body weight changes, oedema, or measurement technique can shift someone near a threshold between categories.

Body Frame Size Calculator

Body Frame Size Calculator

What is body frame size?

How frame size is measured

Frame size and ideal weight

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