Body Surface Area Calculator

Calculate Body Surface Area used in chemotherapy dosing, burns assessment and medical calculations.

Height (cm)

Weight (kg)

Enter height and weight to calculate BSA

BSA formulas explained

Mosteller (1987)

BSA = √(H × W ÷ 3600)

H in cm, W in kg. Simplest formula, widely used in clinical practice today.

DuBois & DuBois (1916)

BSA = 0.007184 × H^0.725 × W^0.425

The original formula. Used for over 100 years. Slight underestimation in obese patients.

Boyd (1935)

BSA = 0.0003207 × H^0.3 × W^(0.7285 − 0.0188 × log₁₀W)

Good for paediatric patients. More complex but handles low weight better.

Haycock (1978)

BSA = 0.024265 × H^0.3964 × W^0.5378

Specifically validated for infants and children. Often preferred in paediatric oncology.

BSA reference by age

Age	Average BSA	Notes
Neonate	0.25 m²	Birth weight ~3.5 kg
2 years	0.5 m²	~12 kg
5 years	0.75 m²	~18 kg
10 years	1.1 m²	~32 kg
Adult female	1.6 m²	~60 kg, 163 cm
Adult male	1.9 m²	~75 kg, 176 cm

Frequently asked questions

Why is BSA used instead of body weight for drug dosing?

BSA correlates better than body weight with organ function, cardiac output, and the clearance of many drugs — particularly chemotherapy agents. Using BSA reduces inter-individual variation in drug exposure and toxicity.

Which BSA formula should I use?

Mosteller is the most commonly used in modern clinical practice due to its simplicity. DuBois is the historical standard. For paediatric patients (especially infants), Haycock or Boyd may be preferred. Your oncologist or pharmacist will specify which formula to use for any given drug.

What is a normal BSA?

For adult men, the average BSA is approximately 1.9 m² (range ~1.6–2.2 m²). For adult women, it is approximately 1.6 m² (range ~1.4–1.9 m²). Children's BSA increases progressively from about 0.25 m² at birth.

Is BSA the same as body surface temperature measurement?

No. BSA is the total skin area of a human body expressed in square metres, used for drug calculations. It is not a temperature measurement. The concept is also used in burn injury assessment — burn percentage is estimated as a fraction of total BSA.

Can I use this calculator for chemotherapy dose calculations?

This calculator is for informational and educational purposes only. All chemotherapy dosing must be performed by a qualified oncologist or clinical pharmacist using verified patient data and institutional protocols. Never use online tools for actual clinical dosing decisions.

BSA calculations are used by medical professionals. Consult your doctor for all dosage decisions. This tool is for reference only.