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Body Composition

Frame Size Calculator

Determine your body frame size — small, medium, or large — using wrist circumference relative to height. Supports metric (cm) and imperial (inches).

Body Frame Size Calculator

r = Height ÷ Wrist Circumference

Unit System
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Body Frame Size

Your body frame size is determined by bone structure, which is genetic. Knowing your frame size helps interpret ideal weight charts more accurately — large-frame people naturally carry more weight and should not compare themselves to the same reference as small-frame people.

Frame Size Classification (r-value = Height ÷ Wrist)

SexSmall FrameMedium FrameLarge Frame
Maler > 10.49.6 – 10.4r < 9.6
Femaler > 11.010.1 – 11.0r < 10.1

Why Frame Size Matters for Your Health Goals

Body frame size determines your bone structure and influences your natural muscle-carrying capacity. A large-framed man may comfortably carry 10–15% more weight than a small-framed man of the same height while remaining healthy. This is why frame size is built into ideal body weight formulas like Hamwi and Devine. Knowing your frame helps you set realistic and appropriate fitness targets.

Frequently Asked Questions

Using a flexible tape measure, wrap it around the narrowest part of your wrist — just below the wrist bone (use your non-dominant hand). Keep the tape snug but not tight. Measure in cm for metric calculation. The narrowest point is typically just proximal to the styloid process (the bony bump on the outside of your wrist).
Yes — large-framed lifters have broader clavicles, thicker wrist bones, and longer muscle bellies that allow more total muscle mass and give a more imposing physique at lower absolute weights. Small-framed lifters can appear very lean and aesthetic at lower body weights. Natural muscle potential models (like Berkhan's) scale with frame size implicitly through height.
Yes — use the thumb-and-finger method: wrap your thumb and middle finger around your opposite wrist just below the wrist bone. If your fingers overlap: small frame. If they just touch: medium frame. If there's a gap: large frame. This is less precise than the r-value method but provides a quick estimate without measuring tools.
Select whichever unit system you prefer using the toggle at the top. Metric (cm) is standard in Europe; Imperial (inches) is preferred in the USA. The calculator converts inches to cm internally before computing the r-value, so the frame size result is identical regardless of which unit you enter. Typical wrist range: 15–20 cm (5.9–7.9 inches) for adults.

Related Calculators

Wrist Size CalculatorCompare your wrist circumference to averages.Calculate → Healthy Weight CalculatorIdeal weight range adjusted for your frame size.Calculate → Body Surface Area CalculatorClinical BSA across 5 validated formulas.Calculate → Shoulder to Waist RatioCalculate your V-taper and aesthetic proportion.Calculate →