Body Frame Size Calculator
This body frame size calculator estimates whether you have a small, medium, or large frame from your height and wrist circumference — a useful adjustment when reading ideal-weight charts.
What frame size means
Frame size is a rough read on your bone structure. Two people of identical height can have noticeably different healthy weights simply because one has a heavier skeleton and broader joints. Wrist circumference is an easy, stable proxy because there's little fat there to confuse the measurement.
How to measure your wrist
- Wrap a tape around the wrist just below the wrist bone, on the hand side.
- Keep the tape snug but not tight.
- Use your dominant hand for consistency.
The method
Divide height by wrist circumference (same units) to get a ratio r, then read it against the cut-offs:
| Frame | Men (r) | Women (r) |
|---|---|---|
| Small | > 10.4 | > 11.0 |
| Medium | 9.6 – 10.4 | 10.1 – 11.0 |
| Large | < 9.6 | < 10.1 |
Worked example
A man 178 cm tall with an 18 cm wrist: r = 178 ÷ 18 ≈ 9.9, which falls in the 9.6–10.4 band — a medium frame.
Using frame size
Frame size doesn't replace a weight formula — it tells you where to sit within a healthy range. Large-frame people belong nearer the top of a healthy ideal weight or BMI band, and small-frame people nearer the bottom. For a composition-based view, add a body fat estimate.
Frequently asked questions
How do I find my frame size?
- Divide your height by your wrist circumference (same units); compare the ratio to the small/medium/large cut-offs for your sex.
Where do I measure my wrist?
- Around the wrist just below the wrist bone, toward the hand, with the tape snug.
Why does frame size matter?
- It explains why a healthy weight isn't identical for everyone of the same height — large-frame people carry more bone and muscle.
Is frame size the same for men and women?
- The method is the same but the ratio thresholds differ because of average build differences.
Does frame size change my ideal weight?
- It shifts where you sit within a healthy range rather than giving a different formula.
Related calculators
Disclaimer. Frame size is an approximation for healthy adults, not a medical measurement or advice.