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Body Surface Area Calculator

Body Surface Area (BSA) quantifies the total exterior surface area of the human body in square metres (m²). In medical physiology, BSA serves as a key

Health & Fitness
Select preferred unit system for height and weight inputs
Standing height (cm in metric, inches in imperial)
Current body mass (kg in metric, lb in imperial)
Formula & Methodology
Mosteller: BSA = √([Height_cm × Weight_kg] ÷ 3600) | Du Bois: BSA = 0.007184 × W_kg^0.425 × H_cm^0.725

Because directly measuring the skin's surface area requires complex coating or 3D photogrammetry, clinicians rely on published empirical formulas. The Mosteller simplified formula (1987) is the most widely adopted in modern medicine. The classic Du Bois & Du Bois formula (1916) and the Haycock formula (1978) provide alternative coefficients that differ by approximately 1% to 2%.

Body Surface Area (Mosteller Baseline: 1.84 m²)

1.84 m² m²

Overview

Body Surface Area (BSA) quantifies the total exterior surface area of the human body in square metres (m²). In medical physiology, BSA serves as a key biometric for normalizing metabolic rate, cardiac index, renal clearance, and pharmacokinetics. This calculator serves as a comprehensive explainer and formula-comparison resource, calculating BSA across all major historical and modern equations.

Educational & Clinical Safety Warning: This calculator is strictly an educational tool and is NOT for clinical use, chemotherapy drug dosing, pediatric fluid replacement, or medical treatment plans. Clinical BSA calculations must be independently computed by licensed medical clinicians using validated medical software.

Worked Examples

Adult Example at 175 cm and 70 kg (Mosteller vs. Du Bois)

Height = 175 cm, Weight = 70 kg, Metric inputs.

  1. Mosteller calculation: (175 × 70) ÷ 3,600 = 12,250 ÷ 3,600 = 3.40277... √(3.40277) = 1.8446... ≈ 1.84 m².
  2. Du Bois calculation: 0.007184 × (70^0.425) × (175^0.725) = 0.007184 × 6.07548 × 42.4116 = 1.8519... ≈ 1.85 m².
  3. Haycock calculation: 0.024265 × (70^0.5378) × (175^0.3964) ≈ 1.86 m².
  4. Note variance: Mosteller (1.84 m²) and Du Bois (1.85 m²) differ by 0.01 m² (~0.5%).
Final Answer: 1.84 m² (Mosteller) | 1.85 m² (Du Bois)

Imperial Adult at 68 inches and 160 pounds

Height = 68 in (172.72 cm), Weight = 160 lb (72.57 kg).

  1. Convert height and weight: Height = 172.72 cm; Weight = 72.57 kg.
  2. Mosteller calculation: √(172.72 × 72.57 ÷ 3,600) = √(3.4818) = 1.8659... ≈ 1.87 m².
  3. Du Bois calculation: 0.007184 × (72.57^0.425) × (172.72^0.725) ≈ 1.87 m².
Final Answer: 1.87 m² Body Surface Area

Comparison Across Population Sizes

Evaluates pediatric, standard adult, and athletic stature differences.

  1. Average adult male BSA in Western populations is approximately 1.9 m².
  2. Average adult female BSA is approximately 1.6 m².
  3. Equations converge within 1% to 2% for standard body mass ratios.
Final Answer: Comprehensive Multi-Formula Comparison Displayed

How to Use This Calculator

  1. Select your preferred measurement units (Centimetres/Kilograms or Inches/Pounds).
  2. Enter accurate standing height and current body weight.
  3. Review the side-by-side comparison across Mosteller, Du Bois, Haycock, Boyd, and Gehan formulas.
  4. Note the explicit clinical warning: do not use this tool for clinical pharmaceutical dosing.

Frequently Asked Questions

What is the average Body Surface Area for adult men and women?
The statistical average BSA for an adult male is approximately 1.9 m² (typically ranging between 1.8 and 2.1 m²), while the average for an adult female is approximately 1.6 m² (ranging between 1.5 and 1.8 m²). Stature, frame, and body weight significantly influence individual values.
Why do Mosteller and Du Bois formulas give slightly different results?
The Du Bois formula was derived in 1916 by measuring nine individual human subjects using paper molds. The Mosteller formula was published in 1987 as a simplified mathematical approximation designed for rapid mental and calculator execution. Because of slight differences in power exponents, they typically vary by 0.5% to 2%.
Why is Body Surface Area used instead of weight for drug dosing?
Many physiological processes (such as basal metabolic rate, cardiac output, glomerular filtration rate, and hepatic drug clearance) correlate more closely with surface area than total weight. Surface area accounts for heat dissipation and metabolic volume without overestimating dosage in patients with excess adipose tissue.
Can I use this website calculator to calculate chemotherapy doses?
No. Absolutely not. Chemotherapeutic agents and immunosuppressants have narrow therapeutic windows where minor calculation differences can cause severe toxicity or under-treatment. Clinical dosing requires verified clinical software, oncology pharmacy verification, and independent double-checks.
Which BSA formula is considered the gold standard in modern hospitals?
The Mosteller formula is currently the most widely adopted equation in North American and European clinical trials and hospital computerized provider order entry (CPOE) systems due to its mathematical simplicity and close agreement with complex multidimensional models.

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Reviewed & Authored by: OnlineConvers Health & Quantitative Science Editorial Team · Last Updated: 2026-10-07
Computes Body Surface Area across five established peer-reviewed equations: (1) Mosteller (1987): BSA (m²) = √([H (cm) × W (kg)] / 3600); (2) Du Bois & Du Bois (1916): BSA = 0.007184 × W^0.425 × H^0.725; (3) Haycock et al. (1978): BSA = 0.024265 × W^0.5378 × H^0.3964; (4) Boyd (1935): BSA = 0.0003207 × H^0.3 × W_grams^(0.7285 − 0.0188 × log10(W_grams)); (5) Gehan & George (1970): BSA = 0.0235 × W^0.51456 × H^0.42246. Canonical units are metric (cm and kg); imperial values are converted using standard exact constants.
Citations: Simplified calculation of body-surface area (New England Journal of Medicine (Mosteller RD, 1987)) · A formula to estimate the approximate surface area if height and weight be known (Archives of Internal Medicine (Du Bois D & Du Bois EF, 1916)) · Geometric method for measuring body surface area: A height-weight formula validated in infants, children, and adults (The Journal of Pediatrics (Haycock GB et al. 1978))