This BSA calculator estimates the body surface area according to your own measurements, and can be then use to dose medication. You can read more on this subject below the form.

Gender: *
Age: *
Weight: *
Height: *
BSA formula: *
Gender: *
Age: *
Weight: *
Height: *
BSA formula: *

How does this BSA calculator work?

This is a useful tool to assess body surface in relation to the personalized data you are asked to input. It comprises of two tabs one for English and one for Metric measurements so you can use the one that suits you best. You are required to input age, gender, weight and height and also choose the BSA formula you want. There are five choices of equations to use and you can repeat the calculation for all of them in turn and for as many combinations of data as you like. You are then given this value along with BMI, body status, ideal body weight and lean body mass.

The BSA calculator can estimate the body surface area by 5 formulas that are presented below:

Estimating body surface area by Boyd’s formula:

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

Estimating body surface area by DuBois’s formula:

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

Estimating body surface area by Gehan & George’sformula:

BSA = 0.0235 * (Height in cm)0.42246 * (Weight in kg)0.51456

Estimating body surface area by Haycock’s formula:

BSA = 0.024265 * (Height in cm)0.3964 * (Weight in kg)0.5378

Estimating body surface area by Mosteller’s formula:

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

The BSA is an assessment made in order to determine the body surface area which is further on used to estimate the medication dose. Please note that the online web form is not intended to be 100% accurate and should be used for general information purposes only.

Example calculations and results

  • Using the English tab, in case of a female, aged 28, weighing 148 lbs at a height of 5ft 6in using the Boyd’s formula:

- Body Surface Area (BSA): 19.221 Square Feet or 1.786 m2

- BMI: 23.888

- Body status based on WHO BMI range: Normal (healthy weight)

- Ideal Body weight is between: 114.62 lbs and 154.89 lbs

- Lean Body Mass: 106.04 lbs

  • Using the Metric tab, in case of a male, aged 35, weighing 93 kg at a height of 173cm using Mosteller’s formula:

- Body Surface Area (BSA): 2.114 m2

- BMI: 31.074

- Body status based on WHO BMI range: Obese Class I (Moderately obese)

- Ideal Body weight is between: 55.37 kg and 74.82 kg

- Lean Body Mass: 65.31 kg

What is the body surface area?

This is a value used to assess the area of the human body and is mostly used for clinical purposes as an indicator of metabolic mass. It helps determine 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. Two of the most known uses of BSA are in IV and in measuring renal function through GFR. So this actually translates to the surface in square metres of one individual’s body and there are formulas that take account of height and weight amongst others in order to determine it.

Here are some of the average body surface areas for different categories of people.

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


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

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

3) Gao B, Klumpen HJ, Gurney H (2008) Dose calculation of anticancer drugs. Expert Opin Drug Metab Toxicol 4 (10): 1307–19

16 Dec, 2014