By Zencalcy Editorial TeamLast reviewed About us
Frame size describes the width of your skeleton relative to your height. It is most often estimated from a wrist measurement because the wrist has little fat and muscle overlying the bone. Frame size is a rough descriptor, not a diagnostic measurement, and it should not be used to justify an unhealthy weight.
Classify frame size from height and wrist circumference.
Frame index = height(cm) ÷ wrist circumference(cm)
Frame size categories from height-to-wrist ratio are a traditional anthropometric shortcut. Men with an index above 10.4 are classified small, 9.6–10.4 medium and below 9.6 large. Women use above 11.0 small, 10.1–11.0 medium and below 10.1 large. The ranges are approximate and vary slightly between reference tables.
| Symbol | Meaning |
|---|---|
| Frame index | Height divided by wrist circumference, both in centimetres. |
| Wrist | Circumference just distal to the wrist crease. |
175 ÷ 17 = 10.29. That falls inside the 9.6–10.4 medium range for men. A 15 cm wrist would give 11.67 and a small classification, while a 19 cm wrist gives 9.21 and a large classification.
Bone width is real, but it explains only a small part of the variation in body weight. Two people of the same height and frame size can differ by many kilograms because of muscle, fat and fluid. That is why frame-size tables were dropped from most modern weight guidance. The measurement is still useful in a few narrow contexts: fitting watch bands and medical devices, interpreting body-fat estimates, and adding nuance when someone sits at the edge of a BMI category with an unusually broad or narrow skeleton. It is not a licence to ignore waist circumference or to accept a high BMI as 'just big bones'. If you use frame size, treat it as one descriptive data point alongside waist, body-fat trend and how you feel and function.
Continue with the ABSI Calculator (A Body Shape Index), Adjusted Body Weight Calculator, or the BAI Calculator (Body Adiposity Index) — or browse more body measurements tools and all health calculators.
Also see the Body Fat Calculator.
Some older ideal-weight tables added 10% for a large frame and subtracted 10% for a small frame. Modern BMI and waist-based guidance already account for overall size, so frame adjustments are optional context rather than a rule.
Every result is a screening estimate from published anthropometric equations, not a diagnosis or a measurement of body composition. Tape measurements should be taken snugly against the skin without compressing it, at the landmarks named in each tool. Equations were derived in specific populations and can be less accurate for athletes, older adults, children, pregnant people and people with significant oedema.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
Content updated: September 2026