Body surface area calculator: height and weight
Calculate body surface area from height and weight, with explicit units and the formula supplied by the tool.
Method
Mosteller: BSA = √(height × weight / 3600)
Use the measurement units shown below. Some fields apply only to a selected method or condition; follow the interactive tool’s method choices. The interactive tool keeps missing measurements incomplete and provides its method-specific results and reference context.
Measurements and acquisition
Height · H cm
Record the units, date and measurement source
- Use measured height and weight where feasible. Record the units, date and whether a value was reported or estimated.
- Fluid status and weight changes affect BSA. Document any substituted weight; do not silently replace measured weight with ideal or dry weight.
- Use the unit named by the field. BSA is in m²; height and weight can be converted in the Body surface area calculator. Keep the formula with serial indexed results.
Weight · W kg
Record the units, date and measurement source
- Use measured height and weight where feasible. Record the units, date and whether a value was reported or estimated.
- Fluid status and weight changes affect BSA. Document any substituted weight; do not silently replace measured weight with ideal or dry weight.
- Use the unit named by the field. BSA is in m²; height and weight can be converted in the Body surface area calculator. Keep the formula with serial indexed results.
Formula
Record the units, date and measurement source
- Mosteller
- Du Bois
- Haycock
- Gehan & George
- Use measured height and weight where feasible. Record the units, date and whether a value was reported or estimated.
- Fluid status and weight changes affect BSA. Document any substituted weight; do not silently replace measured weight with ideal or dry weight.
- Use the unit named by the field. BSA is in m²; height and weight can be converted in the Body surface area calculator. Keep the formula with serial indexed results.
Sources and method context
Primary BSA publications · Height–weight estimates of body surface area · Du Bois 1916 · Gehan & George 1970 · Haycock 1978 · Mosteller 1987
- Mosteller · N Engl J Med 1987;317:1098 · doi:10.1056/NEJM198710223171717
BSA = √(H × W / 3600). H in cm, W in kg, BSA in m². The app defaults to this equation; this is not a claim that every echo reference uses it.
- Du Bois & Du Bois · Arch Intern Med 1916;17:863–871 · doi:10.1001/archinte.1916.00080130010002
BSA = 0.007184 × H^0.725 × W^0.425; H in cm and W in kg.
- Haycock, Schwartz & Wisotsky · J Pediatr 1978;93:62–66 · PMID:650346
BSA = 0.024265 × H^0.3964 × W^0.5378; H in cm and W in kg. The primary study included infants, children and adults.
- Gehan & George · Cancer Chemother Rep 1970;54:225–235 · PMID:5527019
BSA = 0.0235 × H^0.42246 × W^0.51456; H in cm and W in kg.
- Body size and indexed valve area · EACVI/ASE aortic stenosis focused update 2017 · section 1.3 · doi:10.1016/j.echo.2017.02.009
BSA indexing has limitations in obesity: aortic valve area does not grow in proportion to excess weight. Do not infer stenosis severity from an indexed value alone.
- Chamber indexing in obesity · Zong et al. JASE 2014;27:1267–1274 · PMID:25193637
The choice of body-size normalization affects recognition of left-heart enlargement in obesity. Retain raw measurements alongside indexed results.
Catalogue review status: Source mapped · clinical sign-off pending
These pages describe the educational tool. Interpret measurements with the complete clinical context and the method’s acquisition limitations.