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BSA calculator: 70 kg, 170 cm = 1.82 m²

At 70 kg and 170 cm the average BSA is 1.8178 m² (Du Bois 1.8097, Mosteller 1.8181, Haycock 1.8257). Educational estimate, not a clinical dose.

The figures in the title are an example. Change the inputs to see your result.

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Direct answer

At 70 kg and 170 cm (the calculator defaults) the average of Du Bois, Mosteller and Haycock is 1.8178 m² (1.82 m² in the title). Du Bois is 1.8097 m², Mosteller 1.8181 m² and Haycock 1.8257 m². Educational figures: a clinician must verify any dose.

Use the calculator above with your own weight and height. All three formulas update together.

Worked example (engine)

ProfileWeightHeightDu BoisMostellerHaycockAverage
Adult (default)70 kg170 cm1.80971.81811.82571.8178
Taller adult80 kg180 cm1.99642.00002.00662.0010
Lighter adult60 kg160 cm1.62211.63301.64051.6319

Default (70 kg, 170 cm) step by step:

  1. Du Bois (1916): 0.007184 × 70^0.425 × 170^0.725 = 1.8097 m²
  2. Mosteller (1987): √(170 × 70 / 3600) = 1.8181 m²
  3. Haycock (1978): 0.024265 × 70^0.5378 × 170^0.3964 = 1.8257 m²
  4. Average: (1.8097 + 1.8181 + 1.8257) / 3 = 1.8178 m²

What is Body Surface Area (BSA)?

Body Surface Area (BSA) is the total skin area of the body, in square meters (m²). Clinically it is used for:

  • drug dosing, especially chemotherapy
  • burn assessment (rule of nines)
  • cardiac index
  • glomerular filtration rate (GFR)
  • dialysis parameters

It does not replace weight or BMI: BMI classifies weight/height; BSA estimates skin area.

Calculation formulas

Du Bois formula (1916)

Du Bois Formula

BSA = 0.007184 × weight^0.425 × height^0.725

The most widely used clinical standard. The Du Bois brothers derived it by measuring body surface area directly.

Mosteller formula (1987)

Mosteller Formula

BSA = √(height × weight / 3600)

A simplified form that is easy to compute by hand. In average adults it sits within hundredths of Du Bois.

Haycock formula (1978)

Haycock Formula

BSA = 0.024265 × weight^0.5378 × height^0.3964

Developed with pediatric populations; often preferred for children and adolescents.

Reference values

GroupAverage BSA (m²)
Newborn0.25
Child (2 years)0.5
Child (10 years)1.14
Average adult female1.6
Average adult male1.9
Average adult BSA

The average adult BSA is about 1.7 m². It is often used when an individual measurement is unavailable. This page's default (70 kg / 170 cm → 1.8178 m²) sits near that average.

Clinical uses of BSA

Chemotherapy dosing

Many agents are dosed in mg/m². BSA correlates better with blood volume and metabolic function than weight alone. This tool does not calculate a dose: only the area.

Cardiac index

Cardiac Index

CI = Cardiac Output (L/min) / BSA (m²)

The usual cited range is 2.5 to 4.0 L/min/m².

Burn assessment

Total BSA is the reference for the rule of nines when estimating the affected percentage and guiding fluid resuscitation.

Professional medical use

BSA calculations for drug dosing must be performed and verified by healthcare professionals. This calculator is educational. Verified 25 September 2026.

Which formula should I use?

  • Du Bois: standard for most adult clinical applications
  • Mosteller: when a quick calculation is enough
  • Haycock: preferred for pediatric patients

All three are very close in average adults. Differences grow at extreme weight or height.

What is body surface area and what is it used for?

Body Surface Area (BSA) is the measurement of the total skin area of the body in square meters. In medicine, it is used to dose medications (especially chemotherapy), calculate cardiac index, assess burns, and adjust dialysis parameters.

What is the difference between Du Bois, Mosteller, and Haycock formulas?

Du Bois (1916) is the most commonly used clinical standard. Mosteller (1987) is a simplified version using square root. Haycock (1978) was developed for pediatric patients. All three give similar results in average adults.

What is the normal BSA for an adult?

The average adult BSA is approximately 1.7 m². Males typically have a BSA close to 1.9 m² and females around 1.6 m². At 70 kg and 170 cm this calculator averages 1.8178 m².

Why is BSA used instead of weight for drug dosing?

BSA correlates better with blood volume, metabolic rate, and organ function than body weight alone. This allows for more precise dosing, especially for drugs with a narrow therapeutic margin such as chemotherapy.

Can BSA be calculated in children?

Yes. The Haycock formula is the most recommended for children. Pediatric dosing based on BSA is common for many medications. A newborn's BSA is approximately 0.25 m² and increases with growth.

How accurate is the BSA calculation?

BSA formulas are estimates based on mathematical models. All formulas have an error margin of approximately 5-10%. For most clinical applications, this accuracy is sufficient. Direct measurement is more precise but impractical.

How is BSA related to burn assessment?

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