# Body surface area calculator

> Body surface area (BSA) in m² from height and weight by the Mosteller, DuBois and Haycock formulas, with the spread between them.

Versão interativa: https://www.calcopenly.com/pt/health/body-surface-area-calculator
Tema: Calculadoras de saúde e condicionamento

Body surface area (BSA) is the total area of the skin, estimated here from height and weight with three formulas. Mosteller (1987) takes the square root of height in centimetres times weight in kilograms divided by 3600. DuBois (1916) and Haycock (1978) raise weight and height to fitted powers. The spread shows how far the three disagree.

Many chemotherapy drugs are dosed in mg per m², cardiac output is divided by BSA to give cardiac index, and kidney function (eGFR) is reported per 1.73 m². At the default 70 kg and 175 cm, Mosteller gives 1.84 m², and DuBois and Haycock both round to 1.85 m².

For adults of average build the formulas agree within about 1.5 %, but they drift apart in obesity: at 120 kg and 170 cm they range from 2.28 to 2.44 m². Dosing protocols state which formula their doses assume.

## Dados

- **Weight**
- **Altura**: Accepts 5'11" or 5 ft 11 in

## Resultados

- BSA (Mosteller) (m²) — resultado principal
- BSA (DuBois) (m²)
- BSA (Haycock) (m²)
- Spread between formulas

## Fórmula

$$
\text{Mosteller} = \sqrt{\frac{h \cdot w}{3600}},\quad \text{DuBois} = 0.007184\, w^{0.425} h^{0.725},\quad \text{Haycock} = 0.024265\, w^{0.5378} h^{0.3964}\quad(h\ \text{cm},\ w\ \text{kg})
$$

## Exemplos resolvidos

### 70 kg, 175 cm

- Weight: 70 kg
- Altura: 175 cm
- **BSA (Mosteller): 1.84 m²**
- **BSA (DuBois): 1.85 m²**
- **BSA (Haycock): 1.85 m²**
- Fonte de verificação: Python 3.8 math: √(175 × 70 / 3600) = 1.844662; 0.007184 × 70^0.425 × 175^0.725 = 1.848143; 0.024265 × 70^0.5378 × 175^0.3964 = 1.846776

### 200 lb, 6 ft

- Weight: 200 lb
- Altura: 6 ft
- **BSA (Mosteller): 2.15 m²**
- **BSA (DuBois): 2.13 m²**
- **BSA (Haycock): 2.16 m²**
- Fonte de verificação: Python 3.8 math with 90.718474 kg and 182.88 cm: 2.146741, 2.130382, 2.160487

### Child 10 kg, 75 cm

- Weight: 10 kg
- Altura: 75 cm
- **BSA (Mosteller): 0.46 m²**
- **BSA (DuBois): 0.44 m²**
- **BSA (Haycock): 0.46 m²**
- Fonte de verificação: Python 3.8 math: 0.456435, 0.437306, 0.463505

### Edge: newborn 3.5 kg, 50 cm

- Weight: 3.5 kg
- Altura: 50 cm
- **BSA (Mosteller): 0.22 m²**
- **BSA (DuBois): 0.21 m²**
- **BSA (Haycock): 0.22 m²**
- Fonte de verificação: Python 3.8 math: 0.220479, 0.208616, 0.224415

## Perguntas

### What is the average body surface area of an adult?

About 1.8 m². In 3,613 UK adults receiving chemotherapy in 2005, Sacco and colleagues (PLoS One 2010) found a mean of 1.79 m²: 1.91 m² for men and 1.71 m² for women. eGFR is normalised to a reference adult of 1.73 m², so a person with a BSA of 2.1 m² has an absolute kidney filtration rate about 21 % higher than the reported eGFR.

### What is the Mosteller formula?

BSA in m² equals the square root of height in centimetres times weight in kilograms, divided by 3600. For 175 cm and 70 kg that is √(175 × 70 ÷ 3600) = √3.40 = 1.84 m². R. D. Mosteller published it in a 1987 letter to the New England Journal of Medicine as a simpler alternative to the DuBois formula that can be worked out on a pocket calculator.

### Which BSA formula is best for children?

DuBois is the least suited to small children. Haycock and colleagues measured 81 subjects from premature infants to adults and found that the DuBois formula increasingly underestimated surface area below 0.7 m², by 7.96 % in newborns. For a 3.5 kg, 50 cm newborn, DuBois gives 0.209 m² against Haycock's 0.224 m² and Mosteller's 0.220 m². DuBois itself was fitted to only 9 people.

### Why are chemotherapy doses based on body surface area?

Metabolic rate, blood volume and drug clearance were found to scale more closely with surface area than with weight across body sizes, so mg per m² became the standard way to scale cytotoxic doses. A 75 mg/m² dose for a 1.84 m² adult is 138 mg. BSA explains only part of the variation in clearance between patients, and some drugs, such as carboplatin, are dosed on kidney function instead.

### Qual é a precisão de “Body surface area calculator”?

A precisão depende dos dados inseridos e das hipóteses do método. O cálculo decimal usa 50 algarismos significativos, mas estimativas, métodos numéricos e dados de origem podem ter menor precisão; o arredondamento exibido não elimina essas limitações. Exemplos resolvidos verificados com fontes independentes: 4. Por exemplo, “70 kg, 175 cm” é verificado com Python 3.8 math: √(175 × 70 / 3600) = 1.844662; 0.007184 × 70^0.425 × 175^0.725 = 1.848143; 0.024265 × 70^0.5378 × 175^0.3964 = 1.846776.

### De onde vem o método?

Mosteller RD. Simplified calculation of body-surface area. N Engl J Med 1987;317(17):1098; DuBois D, DuBois EF. A formula to estimate the approximate surface area if height and weight be known. Arch Intern Med 1916;17:863–871; Haycock GB, Schwartz GJ, Wisotsky DH. Geometric method for measuring body surface area: a height-weight formula validated in infants, children, and adults. J Pediatr 1978;93(1):62–66.

## Fontes

- [Mosteller RD. Simplified calculation of body-surface area. N Engl J Med 1987;317(17):1098](https://doi.org/10.1056/NEJM198710223171717)
- DuBois D, DuBois EF. A formula to estimate the approximate surface area if height and weight be known. Arch Intern Med 1916;17:863–871
- [Haycock GB, Schwartz GJ, Wisotsky DH. Geometric method for measuring body surface area: a height-weight formula validated in infants, children, and adults. J Pediatr 1978;93(1):62–66](https://doi.org/10.1016/S0022-3476(78)80601-5)

_Apenas informação, não orientação médica. Estas fórmulas descrevem populações, não a sua situação individual; consulte um profissional de saúde antes de agir com base em um resultado._