Body Surface Area (BSA)

Calculates Body Surface Area (Mosteller formula).

Anthropometry General MedicineEvidence-BasedUpdated 2026-08-06

Clinical Notes

Formula

BSA = √((height × weight) / 3600)

Normal Range

Typical adult: 1.4–2.2 m²

Clinical Notes

Interpret results together with the patient's clinical presentation.

References

MedCalcHub Clinical References

Calculator Information

Specialty

General Medicine

📋 Reference Ranges

Normal Range

Typical adult: 1.4–2.2 m²

What This Calculator Measures

Estimates body surface area using the Mosteller formula, used to normalize physiological parameters and to dose selected medications.

How to Use

Measure weight (kg) and height (cm).
Enter both values.
Review the calculated BSA in m².

Interpretation Guide

Typical adult BSA ranges from approximately 1.4–2.2 m². The value is used to index physiological parameters such as cardiac output and to dose certain medications normalized to body surface area.

Clinical Significance

BSA is a standard index in physiology and pharmacology, used to scale physiological variables and guide dosing of several high-risk medications.

When to Use

Dosing medications that are normalized to body surface area
Indexing cardiac output, renal, or other physiological parameters
Assessment of body size in clinical studies

When Not to Use

As a measure of body fatness — use BMI and body composition instead
In place of weight-based dosing where the drug label specifies weight-based dosing
As a substitute for the direct assessment of burn surface area

Limitations

Several BSA formulas exist (Mosteller, DuBois, Haycock) and results differ slightly between them.
Assumes a fixed weight–height relationship that is less accurate at extremes of body habitus.
Is not a measure of body composition.
Pediatric use is common, but the formula chosen should be consistent within an institution.

Worked Example

A 40-year-old woman weighs 70 kg and is 170 cm tall.

Inputs:

weight: 70

height: 170

BSA = √((170 × 70) / 3600) ≈ 1.82 m², within the typical adult range.

Evidence

Source: Anthropometry / Oncology
Reference: Mosteller RD. N Engl J Med. 1987;317(17):1098.
Reviewed By: MedCalcHub Clinical Team
Version: 1987
Updated: 2026-08

Mosteller RD. N Engl J Med. 1987;317(17):1098.

References

Mosteller RD. Simplified calculation of body-surface area. N Engl J Med. 1987;317(17):1098. (Original Description)

Frequently Asked Questions

What is BSA used for?

BSA is used to index physiological parameters (e.g., cardiac output) and to dose certain medications that are normalized to body surface area, particularly in oncology.

Which BSA formula should I use?

The Mosteller formula is most commonly used. Different formulas (DuBois, Haycock) give slightly different results. Use the same formula consistently within your institution.

Is BSA the same as BMI?

No. BSA measures total body surface area in m2. BMI measures weight relative to height squared. BSA is used for dosing and physiological indexing; BMI is a screening tool for body fatness.

Disclaimer: This calculator is intended for educational and clinical decision support purposes only. Dosing decisions must always follow drug-specific labeling and institutional protocols.

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