Calculate Du Bois body surface area from weight and height in kg, lbs, cm, m, inches, or feet, with results in m² or ft² using the Du Bois formula.

Du Bois BSA Calculator

Enter weight and height to calculate Du Bois BSA.

Standard
Feet + inches
ft
in
Body Surface Area
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Medical notice: For informational use only. Do not use this calculator to dose chemotherapy, prescription medicines, or IV fluids—dosing must be determined and verified by a licensed clinician/pharmacist using the specific protocol. BSA methods and rounding rules vary (e.g., Du Bois, Mosteller, Haycock), and results may be less reliable in situations such as children, pregnancy, kidney/liver disease, severe obesity/edema, amputation, burns, dehydration, or critical illness.

Du Bois BSA Formula

The Du Bois BSA calculator uses the Du Bois formula to estimate body surface area from weight and height. The formula requires weight in kilograms and height in centimeters.

BSA = 0.007184 * W⁽0.425) * H⁽0.725)
  • BSA = body surface area in square meters, m²
  • W = weight in kilograms, kg
  • H = height in centimeters, cm

When you enter weight in pounds, the calculator first converts pounds to kilograms.

W₍kg) = W₍lb) * 0.45359237

When you enter height in another unit, the calculator converts it to centimeters before applying the Du Bois formula.

H₍cm) = Hₘ * 100
H₍cm) = Hᵢₙ * 2.54
H₍cm) = H₍ft) * 30.48

In the feet + inches mode, height is combined and converted with this formula:

H₍cm) = (ft * 30.48) + (in * 2.54)

If you choose square feet as the result unit, the calculator converts the BSA result from square meters to square feet.

BSA₍ft²) = BSA₍m²) / 0.09290304
  • Standard mode accepts one weight value and one height value. You can choose kg or lbs for weight and cm, m, in, or ft for height.
  • Feet + inches mode accepts weight plus separate feet and inches fields for height. This is useful when height is written as 5 ft 10 in instead of total inches.
  • Result unit lets you display the final body surface area in m² or ft². The Du Bois calculation itself is performed in kg and cm.

Body Surface Area Reference Ranges

These ranges are general reference points. Actual BSA varies with height, weight, age, and body composition.

BSA result Common interpretation
Less than 0.5 m² Usually seen in small children
0.5 to 1.2 m² Often seen in children
1.2 to 1.6 m² Below a typical adult range
1.6 to 2.1 m² Common adult range
More than 2.1 m² Above the average adult range

Unit Conversions Used for Du Bois BSA

Conversion Formula
Pounds to kilograms lb × 0.45359237
Meters to centimeters m × 100
Inches to centimeters in × 2.54
Feet to centimeters ft × 30.48
Square meters to square feet m² ÷ 0.09290304

Example Calculations

Example 1: BSA using kilograms and centimeters

Suppose your weight is 70 kg and your height is 175 cm.

BSA = 0.007184 * 70⁽0.425) * 175⁽0.725)

The result is approximately 1.8481 m².

Example 2: BSA using pounds and feet plus inches

Suppose your weight is 180 lb and your height is 5 ft 10 in.

W₍kg) = 180 * 0.45359237 = 81.6466
H₍cm) = (5 * 30.48) + (10 * 2.54) = 177.8
BSA = 0.007184 * 81.6466⁽0.425) * 177.8⁽0.725)

The result is approximately 2.0003 m², or about 21.53 ft².

FAQ

What is Du Bois BSA?

Du Bois BSA is an estimate of body surface area calculated from height and weight. It is named after the Du Bois formula, which is commonly written as BSA = 0.007184 × weight0.425 × height0.725, using kilograms and centimeters.

Why does the formula use kg and cm?

The Du Bois formula was defined with weight in kilograms and height in centimeters. If you enter pounds, feet, inches, or meters, those values need to be converted first so the formula stays consistent.

Is Du Bois BSA the same as BMI?

No. BSA estimates the surface area of the body, usually in square meters. BMI estimates weight relative to height, usually in kg/m². They use different formulas and answer different questions.