Body Frame Size Calculator — Wrist Method
Find your body frame size (small, medium or large) from height and wrist size. Get your frame-adjusted ideal weight range. Free, instant.
CalcVita. (2026). Body Frame Size Calculator — Wrist Method. CalcVita. Retrieved September 2, 2026, from https://calcvita.com/en/calculators/body-frame-size
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Enter your height, wrist circumference, sex, and preferred unit. The calculator uses the height-to-wrist ratio method, standardized by the Metropolitan Life Insurance Company, to classify your body frame as small, medium, or large. It then applies a ±10% adjustment to the Devine ideal body weight formula to provide a personalized healthy weight range for your frame type.
How to measure your wrist
Wrap a flexible measuring tape around your wrist at the narrowest point — just above the wrist bone (styloid process), at the joint between your hand and forearm. Keep the tape snug but not tight. Measure in the morning before any swelling occurs. Record the measurement in centimeters (or inches if using imperial). Take it twice and average the readings.
Classification thresholds
Women: ratio > 10.9 = small frame, 9.9–10.9 = medium frame, < 9.9 = large frame. Men: ratio > 10.4 = small frame, 9.6–10.4 = medium frame, < 9.6 = large frame. The ratio is calculated as height (cm) ÷ wrist circumference (cm). Ideal weight is based on the Devine formula adjusted ±10% for frame size, with a ±5% individual range.
Scientific references
- Devine BJ (1974) — Gentamicin therapy. Drug Intelligence & Clinical Pharmacy. 8:650-655. (Source of IBW formula)
- Metropolitan Life Insurance Company (1959) — Build and Blood Pressure Study. Society of Actuaries, Chicago. (Frame size tables)
- Robinson JD et al. (1983) — Determination of ideal body weight for drug dosage calculations. Am J Hosp Pharm. 40(6):1016-9. PMID 6869387
Frequently asked questions
- How is body frame size determined?
- Body frame size is determined using the ratio of height to wrist circumference. This method was popularized by the Metropolitan Life Insurance Company. For women, a ratio above 10.9 indicates a small frame, 9.9–10.9 a medium frame, and below 9.9 a large frame. For men, a ratio above 10.4 indicates small, 9.6–10.4 medium, and below 9.6 large. The wrist is measured at its narrowest point, just distal to the styloid processes.
- Why does frame size affect ideal weight?
- People with different frame sizes have different bone densities and skeletal proportions. A large-framed person will naturally weigh more than a small-framed person of the same height while both being at a healthy weight. Traditional ideal body weight formulas (Devine, Hamwi) were developed for medium-frame individuals, so a ±10% adjustment is applied for small or large frames. The WHO BMI range (18.5–24.9) does not account for frame size and may be less accurate for extreme body types.
- How do I measure my wrist circumference correctly?
- Wrap a measuring tape around your wrist at its narrowest point — just above the wrist bone (styloid process), at the joint between your hand and forearm. Keep the tape snug but not tight. Take the measurement in the morning before any swelling. For most adults, wrist circumference ranges from 14–20 cm (5.5–7.9 inches). Repeat the measurement twice and use the average.
- What is the Devine ideal body weight formula?
- The Devine formula (1974) is one of the most widely used clinical ideal weight equations. For men: IBW = 50 kg + 2.3 kg per inch over 5 feet. For women: IBW = 45.5 kg + 2.3 kg per inch over 5 feet. This calculator uses Devine as the base and adjusts ±10% based on your frame size, then presents a ±5% range around that adjusted value to account for individual variation.
- Is body frame size related to BMI?
- BMI does not account for body frame size, which is one of its limitations. Two people with the same BMI can have very different body compositions depending on their frame size. A large-framed person with a BMI of 25 may be perfectly healthy, while a small-framed person at the same BMI may carry more fat relative to their bone structure. Using both BMI and frame size together provides a more complete picture of healthy weight.
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