Bedridden Patient Height Calculator
Estimate the height (stature) of a bedridden or non-ambulatory adult from their knee height using the Chumlea equation. When a patient can't stand to be measured, knee height combined with age and sex gives a validated estimate of their standing height — useful for BMI, drug dosing and nutrition assessment.
Rates and fees change frequently. Always confirm the current figures
with the official authority before relying on this result.
- Formula validated for adults aged 60–90 years.
- Less accurate in younger individuals or non-white populations.
- Requires accurate knee-height measurement technique.
Formula
Males: Height (cm) = 64.19 − (0.04 × age) + (2.02 × knee height cm)
Females: Height (cm) = 84.88 − (0.24 × age) + (1.83 × knee height cm)
- Uses the Chumlea (1985) knee-height equations to estimate standing height when a patient cannot stand.
- Males: height (cm) = 64.19 − (0.04 × age) + (2.02 × knee height in cm).
- Females: height (cm) = 84.88 − (0.24 × age) + (1.83 × knee height in cm).
- Knee height is measured from the heel to the top of the knee with the leg bent at 90°.
- The equations are validated for adults roughly 60–90 years old and are estimates, not exact measurements.
- Estimated height feeds into BMI, body-surface-area and nutrition calculations for patients who can't be measured standing.
70-year-old man, 48 cm knee height
Inputs
- Sex: male
- Age: 70 years
- Knee Height: 48 cm
Height = 64.19 − (0.04 × 70) + (2.02 × 48) = 64.19 − 2.8 + 96.96 ≈ 158.4 cm (about 5 ft 2 in).
Frequently asked questions
When is this calculator used?
When a patient is bedridden or unable to stand to be measured — for example, in elderly or critically ill patients — and a height estimate is needed for BMI, dosing or nutrition.
How do I measure knee height?
Bend the knee and ankle to 90° and measure from the bottom of the heel to the top of the knee (over the thigh) in centimetres, ideally with a knee-height caliper.
How accurate is the Chumlea formula?
It's a validated estimate for adults aged about 60–90. Accuracy is lower outside that age range and across different ethnic groups, so treat the result as an approximation.
Why estimate height at all?
Height is needed for BMI, body surface area and many drug-dose and nutrition calculations. When direct measurement isn't possible, knee-height estimation is the standard workaround.
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