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Health & Medical

Body Surface Area (BSA) Calculator

Q: What is a normal body surface area?

Adult BSA is typically 1.6 to 1.9 m². 1.73 m² is a common reference for kidney function.

Q: Which BSA formula is most accurate?

The Mosteller formula is most widely used clinically. Du Bois and Haycock are also validated.

Q: How is BSA used in drug dosing?

Total dose equals mg per m² multiplied by calculated BSA. Common in chemotherapy and pediatrics.

Q: Is BSA the same as BMI?

No. BMI uses weight over height squared for weight categories. BSA estimates body surface for medical dosing.

Free BSA calculator using Mosteller, Du Bois, Haycock, and other formulas. Estimate body surface area in m² from height and weight — plus formula comparison, drug dosing by m², and reference ranges.

For education and estimation only. Clinical dosing and treatment decisions require a qualified healthcare provider.

Height & Weight

All BSA formulas use height in cm and weight in kg internally.

Height unit

Weight unit

Height

Weight

Body Surface Area Result

Primary result uses the Mosteller formula — the most widely used BSA equation in clinical practice.

Primary formula

Compare All BSA Formulas

See how different published equations compare for the same height and weight. Values typically agree within a few percent for adults.

BSA-Based Drug Dosing Calculator

Many chemotherapy and pediatric doses are prescribed as mg per m². Total dose = dose rate × body surface area.

Dose rate

mg/m²

BSA formula

Example: If BSA = 1.73 m² and prescribed dose = 50 mg/m², total dose ≈ 86.5 mg. Always verify with prescribing information and a clinician.

BSA Formula Reference

H = height (cm), W = weight (kg). All results in square meters (m²).

Mosteller: BSA = √((H × W) / 3600)

Du Bois: BSA = 0.007184 × H^0.725 × W^0.425

Haycock: BSA = 0.024265 × H^0.3964 × W^0.5378

Gehan & George: BSA = 0.0235 × H^0.42246 × W^0.51456

Boyd: BSA = 0.0003207 × H^0.3 × W(g)^exp (W in grams)

Fujimoto: BSA = 0.008883 × H^0.663 × W^0.444

Typical BSA Ranges

Population	Approx. BSA
Newborn	0.25 m²
Child (~10 years)	1.0 – 1.2 m²
Adult woman (average)	1.6 – 1.7 m²
Adult man (average)	1.7 – 1.9 m²
Tall / heavy adult	2.0 – 2.2 m²

Common Uses of Body Surface Area

Chemotherapy dose scaling (mg/m²)
Pediatric medication dosing
Cardiac index (CO / BSA)
Burn severity (% TBSA)
Renal function indexing (e.g. GFR per 1.73 m²)
Research normalization of metabolic measurements

BSA Examples by Height & Weight

Pre-calculated Mosteller BSA for common profiles. Click a row to load values into the calculator.

Profile	Height	Weight	BSA (Mosteller)

What Is Body Surface Area (BSA)?

Body surface area (BSA) estimates the total skin surface of the human body in square meters (m²). Unlike simple weight-based dosing, BSA accounts for both height and weight, which helps scale drug doses and physiological measurements more proportionally — especially in oncology and pediatrics.

The Mosteller formula — BSA = √((height × weight) / 3600) with height in cm and weight in kg — is the most common equation in hospitals and medical references because it is accurate and easy to calculate.

How to calculate body surface area

Measure height (cm or ft/in) and weight (kg or lbs).
Convert to cm and kg if needed.
Apply a BSA formula — Mosteller is the standard clinical choice.
Result is in m² (multiply by 10,000 for cm²).

Example: BSA for 170 cm and 70 kg

Using Mosteller: √((170 × 70) / 3600) = √(11900 / 3600) ≈ 1.82 m² (about 18,200 cm²). An adult reference BSA of 1.73 m² is often used when normalizing kidney function (eGFR).

BSA vs BMI — what's the difference?

Measure	Formula basis	Main use
BMI	Weight ÷ height²	Weight category (underweight, normal, obese)
BSA	Height & weight combined (surface model)	Drug dosing, burns, cardiac index, research

Related health calculators

Body Surface Area FAQ

What is a normal body surface area?

For adults, BSA typically falls between 1.6 and 1.9 m². The value 1.73 m² is often used as a reference standard in kidney function reporting.

Which BSA formula is most accurate?

The Mosteller formula is the most widely used in clinical practice. Du Bois and Haycock are also validated. Differences between formulas are usually small for adults.

How is BSA used in drug dosing?

Many chemotherapy drugs are dosed in mg per m². Total dose = prescribed rate × calculated BSA. Always follow official prescribing guidelines and clinician orders.

How do I convert BSA from m² to cm²?

Multiply square meters by 10,000. Example: 1.82 m² × 10,000 = 18,200 cm².

Is BSA the same as BMI?

No. BMI classifies weight relative to height squared. BSA estimates total body surface and is used mainly for medical dosing and physiological indexing.

Health and Fitness

Calculate your body surface area, which is useful for medical dosing calculations, especially in treatments like chemotherapy. Use our Body Surface Area Calculator to find accurate BSA values for adults and children using weight, height, or pediatric-specific formulas. Includes oncology BSA tools for chemotherapy dosing, detailed charts, and BMI calculator integration for comprehensive health assessment.

Body Surface Area (BSA)

Body Surface Area refers to the total skin area of the human body and is one of the main measurements doctors use in medicine. Body surface area measurement helps determine accurate dosages of drugs. BSA shows metabolic mass more accurately than body weight.

What Is Body Surface Area?

Body Surface Area is the total skin area of the body of a person. It is used in medicine to calculate the accurate dosages of a drug for a patient, especially for chemotherapy treatment. This measurement is also used to determine fluid requirements administered intravenously.

How Body Surface Area Is Calculated?

There are a number of equations you can use to calculate the body surface area.

DuBois & DuBois

BSA(m2) = 0.007184 × Height(cm)0.725 × Weight(kg)0.425

Gehan & George

BSA(m2) = 0.0235 × Height(cm)0.42246 × Weight(kg)0.51456

Haycock et al.

BSA(m2) = 0.024265 × Height(cm)0.3964 × Weight(kg)0.5378

Mosteller

BSA(m2) = SQR RT ([Height(cm) × Weight(kg)]/ 3600)

Average Value Of Body Surface Area

The average value of body surface area is 1.7 m⊃2;. Here is the average value of the body surface area of men and women.

For adult men = 1.9 m⊃2;
For adult women = 1.6 m⊃2;
For newborns = 0.25 m⊃2;

Mean Body Surface Area By Age

Here is the mean body surface area of males and females by age.

Mean body surface area of males by age

Age or Age Group	Metric (m⊃2;)	Imperial (ft⊃2;)
Newborn	0.243 m⊃2;	2.612 ft⊃2;
2 years	0.563 m⊃2;	6.060 ft⊃2;
5 years	0.787 m⊃2;	8.471 ft⊃2;
10 years	1.236 m⊃2;	13.304 ft⊃2;
13 years	1.603 m⊃2;	17.255 ft⊃2;
18 years	1.980 m⊃2;	21.313 ft⊃2;
20–79 years	2.060 m⊃2;	22.173 ft⊃2;
80+ years	1.920 m⊃2;	20.667 ft⊃2;

Mean body surface area of females by age

Age or Age Group	Metric (m⊃2;)	Imperial (ft⊃2;)
Newborn	0.234 m⊃2;	2.519 ft⊃2;
2 years	0.540 m⊃2;	5.813 ft⊃2;
5 years	0.771 m⊃2;	8.299 ft⊃2;
10 years	1.245 m⊃2;	13.401 ft⊃2;
13 years	1.550 m⊃2;	16.684 ft⊃2;
18 years	1.726 m⊃2;	18.579 ft⊃2;
20–79 years	1.830 m⊃2;	19.697 ft⊃2;
80+ years	1.638 m⊃2;	17.631 ft⊃2;

Published

2025-10-02 13:44:28

Updated

2025-10-02 13:44:28

Author

Taylor Bennett