How this calculator works
The MUST report provides separate ulna equations by sex and age band, and knee equations developed in white American adults. These are population estimates, not interchangeable measurements. The form rejects the ambiguous original band boundaries at 65 for ulna and 60 for knee rather than choosing a constant. Other published height and weight models are not included. The result is an estimate for information only and is not medical advice.
Formula
Ulna U in cm: male below 65, H = 79.2 + 3.60U; above 65, 86.3 + 3.15U. Female below 65, 95.6 + 2.77U; above 65, 80.4 + 3.25U. Knee K: males under 60, 71.85 + 1.88K; over 60, 59.01 + 2.08K. Females under 60, 70.25 + 1.87K - 0.06age; over 60, 75 + 1.91K - 0.17age.
Worked example
For a 70-year-old male with a 26 cm ulna, estimated height is 86.3 + 3.15 x 26 = 168.2 cm. A 40-year-old female with a 25 cm ulna gives 164.85 cm.
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Frequently asked questions
How is ulna length measured?
Measure between the elbow tip and the prominent wrist bone with the arm bent across the chest. A trained observer improves consistency.
How is knee height measured in bed?
The knee and ankle are held at right angles and the heel-to-thigh distance is measured using the method described by BAPEN.
Does this replace measured height?
No. Joint deformity, severe spinal curvature and population differences can make the estimate unsuitable. Use direct or reliably recalled height when appropriate.