How to Measure Height Without Standing
For many elderly or ICU patients, standing against a wall is impossible due to weakness, paralysis, or severe spinal compression (kyphosis).
The solution lies in the Tibia (shin bone). Unlike the spine, which compresses with age, the long bones of the leg maintain their length. Dr. Chumlea discovered in 1985 that Knee Height perfectly correlates with true standing height, allowing nurses to "reverse engineer" a patient's stature.
Instructions for Nurses
- Patient lies flat on their back (supine).
- Bend the left knee and ankle to a 90-degree angle.
- Use a caliper or tape measure to measure from the base of the heel to the top of the knee cap (patella).
- Enter the value in centimeters into the calculator above.
Frequently Asked Questions
Why is accurate height important for bedridden patients?
Height is required to calculate BMI (Body Mass Index) and Ideal Body Weight. Without these numbers, dietitians cannot calculate the correct calorie needs for tube feeding, and pharmacists cannot dose dangerous drugs (like chemotherapy or antibiotics) safely. Guessing height often leads to under-dosing or overdosing.
How accurate is the Chumlea equation?
It is accurate to within 3 to 4 cm of actual standing height for 95% of the population. It is considered the "Gold Standard" for geriatric assessment. However, it is less accurate for people with extremely short limbs (dwarfism) or limb deformities/amputations.
Does height shrink with age?
Yes. Due to spinal disc compression and osteoporosis, people typically lose 1-2 inches of height as they age. However, the long bones of the leg (tibia/femur) do not shrink. This is why the Knee Height method is often more accurate than trying to measure a hunched-over elderly patient with a tape measure.
Can I use Arm Span instead?
Yes, Arm Span (fingertip to fingertip) is another valid alternative (demispan). However, arm span can be difficult to measure in patients with stroke contractures or shoulder mobility issues. Knee height is generally preferred in ICU settings because the legs are easier to access and manipulate.
Is this valid for children?
No. The Chumlea equations are specifically calibrated for adults and the elderly (age 60+). Children have different limb-to-torso growth ratios. For children who cannot stand, pediatricians use recumbent length (laying flat) measured with a stadiometer board.
References
- Chumlea WC, et al. (1985). Estimating stature from knee height for persons 60 to 90 years of age. Journal of the American Geriatrics Society.
- Today's Dietitian. Anthropometric Measurements in the Elderly.
- British Association for Parenteral and Enteral Nutrition (BAPEN). Estimating Height from Ulna Length and Knee Height.
Tools & Data Verified by the EverydayCalculators Medical Research Team.
Last updated: January 2026.