What Is Body Surface Area (BSA)?
Body Surface Area (BSA) estimates the total surface area of the human body, calculated from height and weight. It's widely used in clinical medicine — most notably for calculating medication dosages (especially chemotherapy) and certain cardiac and kidney function measurements, since BSA often correlates better with metabolic processes than weight alone.
How to Use the BSA Calculator
- Enter your weight.
- Enter your height.
- Compare BSA estimates from three commonly used formulas.
Body Surface Area Formulas
Worked Example
Du Bois: 0.007184 × 72.6^0.425 × 172.7^0.725 ≈ 1.87 m²
Mosteller: √(172.7 × 72.6 / 3600) ≈ 1.87 m²
The formulas typically agree closely for average adult body types.
Understanding Your Results
BSA is expressed in square meters (m²). The Mosteller formula is simpler to calculate and widely used in clinical practice; the Du Bois formula is historically one of the most established. All three formulas typically produce results within a small margin of each other for average body types.
Why BSA Matters Clinically
BSA-based dosing is used because many physiological processes (like drug clearance, cardiac output, and kidney filtration) scale more closely with body surface area than with weight alone — particularly important for medications with a narrow safety margin, like many chemotherapy drugs.
Important Notes
- Medical dosing decisions should always be made by a qualified healthcare provider using validated clinical tools — this calculator is for general educational reference only.
- Different formulas can produce slightly different results, and clinical protocols may specify which formula to use.
Frequently Asked Questions
It's primarily used in medicine for calculating medication dosages (especially chemotherapy), and for certain cardiac and kidney function measurements, since many physiological processes correlate with BSA.
The Mosteller and Du Bois formulas are both widely used and generally produce similar results; specific clinical protocols may specify which formula to use for a given purpose.
BSA estimates total body surface area (in square meters), while BMI estimates a weight-to-height ratio used for general weight category screening — they measure different things for different purposes.
No — this tool is for general educational reference only. Medical dosing should always be determined by a qualified healthcare provider using validated clinical tools and protocols.
Surface area and volume don't scale at the same rate as an organism's size increases, so BSA calculations account for this relationship better than simple weight-based estimates for certain physiological processes.