Body Surface Area Calculator (BSA)
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/5/2026
Body surface area (BSA) is estimated with the Mosteller formula: √((height in cm × weight in kg) ÷ 3600). For 170 cm and 70 kg, the body surface area is about 1.82 m².
Explanation
Body surface area (BSA) is an estimate of a person's total skin surface, expressed in square meters. It is used in physiology and medicine, notably to calculate certain drug dosages (particularly in oncology) more precisely than weight alone, since it accounts for both height and body mass. Several formulas exist (Mosteller, DuBois, Haycock); this calculator uses the Mosteller formula, the simplest and one of the most widely used in clinical practice. This result is an estimate for informational purposes: an actual medical dosage must always be determined by a healthcare professional, never by this calculator. For body mass index, another indicator based on height and weight, see our BMI calculator.
Example: 170 cm, 70 kg
Inputs
Height: 170 cm. Weight: 70 kg.
Calculation
Body surface area = √((170 × 70) ÷ 3600) = √(11,900 ÷ 3600) = √3.3056 ≈ 1.82.
Result
The estimated body surface area is about 1.82 m².
Frequently asked questions
What is body surface area used for in medicine?
It's mainly used to calculate certain drug dosages (especially in chemotherapy) proportionally to a patient's body size, more precisely than weight alone for some treatments. This calculation is always determined and validated by a healthcare professional, never by an online tool.
Is the Mosteller formula the only one that exists?
No, several estimation formulas exist (DuBois and DuBois, Haycock, Gehan and George...), which give slightly different results. The Mosteller formula is used here for its simplicity and because it remains one of the most widely used in everyday practice.
What's the average body surface area for an adult?
It typically falls between 1.5 and 2.2 m² for an adult, depending on height and build. An average-height man (175 cm, 75 kg) has a body surface area of about 1.90 m² according to the Mosteller formula.