Body Frame Size Calculator
Determine your body frame size (small, medium, or large) using wrist circumference and height.
Helps interpret ideal weight ranges.
Body frame size is assessed using the wrist circumference method — a quick anthropometric measurement that helps determine whether a person’s skeleton is small, medium, or large framed. Frame size matters because ideal weight ranges differ significantly between frame types.
The primary formula uses the r-value (Height-to-Wrist ratio):
r = Height (cm) / Wrist Circumference (cm)
Frame size for women is classified as:
- Small frame: r > 10.9
- Medium frame: r = 10.1–10.9
- Large frame: r < 10.1
Frame size for men is classified as:
- Small frame: r > 10.4
- Medium frame: r = 9.6–10.4
- Large frame: r < 9.6
An alternative method uses elbow breadth measured with calipers and compared against gender/height tables from the Metropolitan Life Insurance Company (1983 reference values).
Worked Example: A woman who is 165 cm tall with a wrist circumference of 15.5 cm:
- r = 165 / 15.5 = 10.65
- Since 10.1 < 10.65 < 10.9 → Medium frame
Her healthy weight range using the Hamwi formula:
- Base: 100 lbs for 5 ft + 5 lbs/inch above 5 ft = 125 lbs
- Medium frame: ±0%, so range = 125 ± 10% = 112.5–137.5 lbs (51–62 kg)
- Large frame: add 10% → 137.5 lbs max
- Small frame: subtract 10% → 112.5 lbs min
Frame size has no bearing on BMI calculation, which is why BMI alone is an incomplete health metric — two people at the same height and weight can have very different healthy weight ranges based on bone structure.