Body Surface Area
1.752 m²
Mosteller formulaMean 1.757 m²
FormulaBSA (m²)
Mosteller1.752
DuBois1.754
Haycock1.754
GehanGeorge1.763
Boyd1.762

Introduction:

Body surface area (BSA) expresses the external covering of a human body in square metres. Clinicians and pharmacologists prefer BSA over body-weight alone because many physiological processes—drug distribution, metabolic heat exchange, cardiac output—scale to surface rather than mass. The metric therefore appears frequently in chemotherapy dosing, renal-clearance equations, and critical-care fluid calculations.

The calculator converts height and weight into centimetres and kilograms, then runs five peer-reviewed equations—Mosteller, Du Bois, Haycock, Gehan-George, and Boyd. Your chosen formula provides the headline value, while the tool contrasts every equation side-by-side, plots bar charts through an in-browser charting layer, and supplies a comma-separated file for offline analysis.

Imagine an oncology pharmacist adjusting a paediatric cisplatin dose; entering 110 cm and 18 kg delivers a 0.71 m² BSA, instantly revealing how alternative methods differ. Values are approximations; always corroborate with institutional standards. This calculator offers informational estimates, not medical advice.

Technical Details:

Body-surface computation treats the human body as a geometric solid whose area relates more directly to metabolic need than outright mass. Empirical studies since 1916 produced several formulae that approximate true surface within ±5 %. Key variables are height (H, cm), weight (W, kg), and for one method weight in grams (Wg).

Core equations:
  • BSA= H×W 3600 – Mosteller
  • BSA=0.20247× H/1000.725 ×W0.425 – Du Bois
  • Haycock – 0.024265×H0.3964×W0.5378
  • Gehan-George – 0.0235×H0.42246×W0.51456
  • Boyd – 0.0003207×H0.3×Wg0.72850.0188×logWg
PopulationTypical BSA (m²)
Newborn0.20 – 0.25
3-year-old child0.60 – 0.70
Adult female (50 kg, 160 cm)1.50 – 1.65
Adult male (70 kg, 175 cm)1.75 – 1.95

Values guide drug-dose nomograms, hyperthermia indexes, and ventilatory settings; they are not thresholds for health classification.

  • height_value – numeric stature entered by user.
  • height_unit – centimetres, metres, or inches.
  • weight_value – numeric mass entered by user.
  • weight_unit – kilograms or pounds.
  • formula – selected computational model.

Mosteller example (170 cm, 65 kg):

170×65=11050 11050÷3600=3.0694 3.0694=1.75 m2
  • Height and weight are measured accurately and represent current physiology.
  • Equations assume normal body composition and hydration.
  • Formulas were derived from specific demographic cohorts; extremes of age or obesity may deviate.
  • All outputs are continuous estimates and lack built-in rounding for clinical protocols.
  • Height ≤ 30 cm or ≥ 250 cm produces extrapolated results.
  • Weights below 1 kg or above 300 kg exceed validation data.
  • Inconsistent unit selection causes unrealistic ratios.
  • Boyd formula diverges when logarithm term approaches zero.

Core research includes Du Bois & Du Bois (1916), Mosteller (1987), Haycock et al. (1978), Gehan & George (1970), and Boyd (1935), each correlating anthropometric data with body area measurements via planimetry or calorimetry.

All calculations run locally in your browser and process no personally identifiable data, aligning with GDPR principles.

Step-by-Step Guide:

Follow the sequence below to obtain and compare body-surface estimates:

  1. Choose centimetres or metres/inches for height.
  2. Enter the height value; ensure positive numbers only.
  3. Select kilograms or pounds for weight, then input the mass.
  4. Pick a formula to spotlight; defaults to Mosteller.
  5. Review the summary box, switch tabs for tables or charts, and press Download CSV to archive results.

FAQ:

Is my data stored?

No. Inputs remain in the browser session and disappear when the tab closes.

Which formula should I use?

Mosteller is widely accepted for adult dosing; paediatric studies often favour Haycock. Compare outputs and follow institutional policy.

Why do values differ?

Each equation weights height and weight exponents differently, reflecting its original validation cohort.

Can I input imperial units?

Yes. Select inches for height or pounds for weight; the tool converts internally to metric.

Does obesity reduce accuracy?

Extreme adiposity shifts surface-to-mass ratios, so all formulae may under-predict actual area; verify with clinical references.

Glossary:

BSA
Body Surface Area, expressed in square metres.
Mosteller
Root-mean-square equation simplifying Du Bois constants.
Nomogram
Graphical tool linking BSA to drug doses.
Anthropometry
Measurement science of human body dimensions.
Metabolic Scaling
Relationship between body measurements and energy use.
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