# 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.

操作できるページ：https://www.calcopenly.com/ja/health/body-surface-area-calculator
分野：健康とフィットネスの計算機

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.

## 入力

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

## 結果

- BSA (Mosteller) (m²) — 主な結果
- BSA (DuBois) (m²)
- BSA (Haycock) (m²)
- Spread between formulas

## 計算式

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

## 計算例

### 70 kg, 175 cm

- Weight: 70 kg
- 高さ: 175 cm
- **BSA (Mosteller): 1.84 m²**
- **BSA (DuBois): 1.85 m²**
- **BSA (Haycock): 1.85 m²**
- 照合元：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
- 高さ: 6 ft
- **BSA (Mosteller): 2.15 m²**
- **BSA (DuBois): 2.13 m²**
- **BSA (Haycock): 2.16 m²**
- 照合元：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
- 高さ: 75 cm
- **BSA (Mosteller): 0.46 m²**
- **BSA (DuBois): 0.44 m²**
- **BSA (Haycock): 0.46 m²**
- 照合元：Python 3.8 math: 0.456435, 0.437306, 0.463505

### Edge: newborn 3.5 kg, 50 cm

- Weight: 3.5 kg
- 高さ: 50 cm
- **BSA (Mosteller): 0.22 m²**
- **BSA (DuBois): 0.21 m²**
- **BSA (Haycock): 0.22 m²**
- 照合元：Python 3.8 math: 0.220479, 0.208616, 0.224415

## よくある質問

### 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.

### 「Body surface area calculator」の精度はどのくらいですか？

精度は入力値と計算方法の前提に依存します。十進演算には有効数字50桁を使いますが、推定、数値計算手法、元データの精度はそれより低い場合があります。表示の丸め処理でこれらの制約がなくなるわけではありません。 独立した出典の解答と照合した計算例：4。 例えば、「70 kg, 175 cm」は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と照合しています。

### この計算方法の出典は何ですか？

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.

## 出典

- [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)

_情報提供のみで、医療上の助言ではありません。これらの式は集団を表すもので、個人の状態を評価するものではありません。結果に基づいて行動する前に医療専門家へ相談してください。_