Health

Body Surface Area Calculator

Calculate your BSA using DuBois, Mosteller, and Haycock formulas for clinical and medical applications

Quick Answer:The average adult BSA is 1.7-2.0 m² in 2026. For a person 175 cm tall weighing 70 kg, the DuBois formula estimates BSA at approximately 1.85 m², which is used for drug dosing and clinical assessments.

Measurements

BSA (DuBois Formula)

Calculating... m²

Mosteller BSA

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Haycock BSA

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Average BSA

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BSA Category

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Formula Comparison

DuBois-- m²
Mosteller-- m²
Haycock-- m²

Expert Insight 2026 Pro Tip

BSA-based drug dosing has been the oncology standard for over 60 years, but 2026 research increasingly supports pharmacogenomic-guided dosing for many agents. The DuBois formula remains the default for most clinical applications, with differences between formulas typically under 5% for average-sized adults. For pediatric patients, the Haycock formula is preferred as it was specifically validated for children and produces more accurate results than DuBois or Mosteller in younger populations.

Frequently Asked Questions

What is Body Surface Area and why is it important in medicine?

Body Surface Area (BSA) is a measurement of the total surface area of the human body expressed in square meters. It is critically important in medicine because many physiological processes, including metabolic rate, drug clearance, and cardiac output, correlate more closely with BSA than with body weight alone. Oncologists use BSA extensively to calculate chemotherapy dosing because drug distribution and clearance scale with surface area rather than weight, reducing the risk of under-dosing in larger patients or overdosing in smaller ones. BSA is also used to calculate the Cardiac Index by dividing cardiac output by BSA, which provides a size-adjusted measure of heart function. Burns treatment relies on BSA to estimate the percentage of body surface affected using the Rule of Nines. The average adult BSA ranges from 1.7 to 2.0 square meters.

Which BSA formula should I use for the most accurate result?

The choice of BSA formula depends on the patient population and clinical context. The DuBois formula, published in 1916, remains the most widely used and is the standard in most clinical settings and drug dosing protocols. However, it was derived from only nine subjects and tends to underestimate BSA in obese individuals. The Mosteller formula is popular due to its simplicity and provides results very similar to DuBois for normal-weight adults. The Haycock formula was specifically developed for pediatric populations and performs best for children and infants. For obese patients with BMI over 30, some clinicians prefer the Livingston formula which was validated across a wider range of body sizes. In practice, the differences between formulas are typically less than 5% for average-sized adults, making the choice less critical for general health assessments.

How is BSA used to calculate chemotherapy doses?

Chemotherapy dosing based on BSA has been the standard practice in oncology since the 1950s, and it remains widely used in 2026 despite ongoing debate about its precision. The dose is calculated by multiplying the drug's recommended dose per square meter by the patient's BSA. For example, if a drug is prescribed at 75 mg per square meter and the patient's BSA is 1.85 square meters, the dose would be approximately 139 mg. This approach aims to standardize drug exposure across patients of different sizes, since larger patients have greater blood volume and organ mass to process the drug. However, research has shown that BSA-based dosing does not fully account for individual variation in drug metabolism, and pharmacogenomic-guided dosing is increasingly supplementing BSA calculations for many agents. Some newer targeted therapies use flat fixed doses rather than BSA-based calculations.

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