Body Surface Area (BSA) Calculator

Estimates body surface area based on age, gender, height and weight by 5 different formulas.

BSA formula
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BSA formula

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Steps on how to print your input & results:

1. Fill in the calculator/tool with your values and/or your answer choices and press Calculate.

2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.

Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.

The five methods to calculate BSA

Body surface area represents the total surface of the human body and its determination has several applications in medicine such as IV fluid measurements and drug dosage.

There are several estimation formulas available for use, the most common one being that published by Mosteller in 1987.

  • Mosteller’s formula

BSA = (((Height in cm) * (Weight in kg))/ 3600)½

  • Boyd’s formula

BSA = 0.0003207 * (Height in cm)0.3 * (Weight in gm)(0.7285 - ( 0.0188 x Log(grams))

  • DuBois’s formula

BSA = 0.007184 * (Height in cm)0.725 * (Weight in kg)0.425

  • Gehan & George’s formula

BSA = 0.0235 * (Height in cm)42246 * (Weight in kg)0.51456

  • Haycock’s formula:

BSA = 0.024265 * (Height in cm)3964 * (Weight in kg)0.5378

Average BSA determinations

Children (9 years) 1.07 m2
Children (10 years) 1.14 m2
Children (12-14 years) 1.33 m2
Adult women 1.6 m2
Adult men 1.9 m2

Other applications for BSA

BSA estimates help with the dosage of various medications that are more sensible and have different clearance times. This is important in order to avoid both over dosage and under dosage.

Renal function is measured by the glomerular filtration rate (GRF) which is calculated in regard to the body surface area.

The Cardiac Index is determined by dividing cardiac output by the body surface area.

Please note that whilst all care has been taken and the original formulas for BSA have been used, this online web form is not intended to be 100% accurate and should be used for general information purposes only.


Mosteller RD. Simplified calculation of body-surface area. N Engl J Med. 1987; 317:1098.

Du Bois D, Du Bois EF A formula to estimate the approximate surface area if height and weight be known. Archives of Internal Medicine. 1916; 17 (6): 863–71

Joo-Young Lee, Jeong-Wha Choi, Ho Kim. Determination of Body Surface Area and Formulas to Estimate Body Surface Area Using the Alginate Method. J Physiol Anthropol. 2008;27(2):71-82. doi: 10.2114/jpa2.27.71.

Specialty: Fitness

Article By: Denise Nedea

Published On: May 23, 2020

Last Checked: May 23, 2020

Next Review: May 23, 2025