🦴 Body Frame Size Calculator
Estimate whether your skeletal frame is small, medium, or large using your wrist circumference and height. This tool computes the standard height ÷ wrist ratio and also offers a height-band cross-check (women only) for extra context.
What body frame size means and how to use it
Body frame size is a simple method to estimate the breadth of your skeletal build — often described as small, medium or large. It is commonly used in nutrition and weight-target formulas to adjust 'ideal' weight ranges, and in fitness contexts to help explain why two people of identical height may carry different weights even with similar body fat percentages.
How the wrist method works
The most common approach compares your height to your wrist circumference. The calculator computes a ratio (height ÷ wrist circumference, both in inches) and applies standard cutoffs that differ for women and men. This method is popular because wrists have little muscle or fat, making them useful proxies for skeletal breadth.
Why results can differ by method
Some sources use direct wrist thresholds that vary by height band (particularly for women) rather than a single ratio cutoff. Both approaches are practical heuristics — they provide guidance rather than a definitive medical diagnosis. When a ratio result and a height-band check disagree, treat the classification as approximate and consider overall body composition and clinical context.
Practical uses and limitations
- Use frame size as one input when estimating target weight ranges or interpreting BMI; it is not a direct measure of bone density.
- Frame size does not determine health — muscle mass, fat distribution, fitness and metabolic health matter much more.
- The method is intended for adults. For children and adolescents, use pediatric growth charts and clinician assessment.
Measuring tips
- Measure standing height without shoes, with heels against a wall.
- Measure wrist circumference at the smallest narrow point, above the wrist bone.
- Use consistent units (this tool converts automatically between cm and inches).
Disclaimer: This tool provides an estimate based on standard methods used in nutrition and fitness guidance. It is informational only and not a substitute for clinical evaluation.
Frequently Asked Questions (FAQs)
The wrist-to-height ratio is simple and widely used; other charts use wrist thresholds by height. None measure bone density — both are approximations.
Skeletal frame size is essentially fixed in adulthood; wrist circumference can change slightly with muscle/fat but large changes are unlikely.
No — this calculator is intended for adults. Use pediatric growth and developmental charts for children.
It can help tailor ideal-weight ranges and interpret body composition, but it should be used with other measures (waist, BMI, body fat).
Not directly — frame is a structural trait. Health depends on overall body composition and metabolic markers.
Either cm or inches are fine — the tool converts automatically. Choose whatever you measured with.
If you're borderline, consider both ratio and height-band cross-check and use your clinical context (family build, ancestry).
No — bone density requires clinical tests (DEXA) and cannot be inferred reliably from wrist circumference.
Some ideal-weight formulas adjust by frame size; use them as a starting point and consult a clinician or dietitian for personalized targets.
Yes — click the Download CSV button after calculating to save your inputs and classification.