What this calculator does
Height and weight tables once came with a frame-size adjustment, on the reasoning that two people of the same height can have genuinely different skeletal builds. Wrist circumference is the usual proxy, since there is very little soft tissue there to confuse the measurement.
The classification is a ratio, not a measurement of bone. At 165 cm, a 14 cm wrist gives a ratio of 11.79 and a small frame, while a 17 cm wrist gives 9.71 and a large one, on identical height.
The formula
Height and wrist circumference are converted to inches and divided. The resulting ratio is compared against separate bands for men and women.
| Term | Meaning |
|---|---|
| Frame size | A rough classification of skeletal build as small, medium or large. |
| Height-to-wrist ratio | Height divided by wrist circumference, both in the same units. |
| Sex-specific bands | Different cut-offs for men and women, reflecting average build differences. |
The inputs explained
| Field | What to enter |
|---|---|
| Sex | Sex, which selects the band thresholds. The two sets differ noticeably. |
| Height (cm) | Height in centimetres. |
| Wrist circumference (cm) | Wrist circumference in centimetres, measured at the narrowest point just below the wrist bone. |
When to use it
Adjusting an ideal weight range
Older height and weight tables list separate ranges by frame size.
Putting a BMI in context
Frame is one of the things BMI cannot see.
Understanding an older reference table
Metropolitan Life tables and similar all used frame adjustments.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How does wrist size change the classification?
The same height at four wrist circumferences.
| Wrist circumference | Frame size | Height-to-wrist ratio (r) |
|---|---|---|
| 14 cm | Small frame | 11.79 |
| 15.5 cm | Medium frame | 10.65 |
| 17 cm | Large frame | 9.71 |
| 19 cm | Large frame | 8.68 |
Questions
How much does frame size actually matter?
Less than the older tables implied. Frame adjustments could shift a recommended weight range by several kilograms, but the underlying evidence was never strong, and modern guidance has largely dropped them.
Why the wrist?
Because it has very little muscle or fat over the bone, so the circumference reflects skeletal size more directly than almost anywhere else that is easy to measure.
Are elbow breadth methods better?
They were the method the Metropolitan Life tables actually used, and they are arguably more reliable, but they need calipers. The wrist method survives because a tape measure is all it requires.
Should I adjust my weight target for this?
Not on your own. Frame size is a crude classification, and healthy weight ranges are better discussed with a doctor who can account for far more than skeletal build.
For the standard weight-for-height measure, see the BMI calculator. For a reference weight from height, see the ideal weight calculator.