Body Surface Area Calculator for medication doses

Calculates BSA for medication doses and includes descriptive statistics.

Step 1. Enter Height & Weight then click "Calculate".

 using Formula: 
click for info re: Body Surface Area formulas

Body Surface Area = m2


Step 2.  Safety Check.  Set Age and Gender, then re-Calculate.

Body description: 

Step 3. Optional Medication Dose Calculator

Multiply BSA m2  x  Dose/m2



Additional Statistics:

Height is at:  Compared to
others of same Age
Weight is at: 
Weight is at:  Compared to
others of same Height

Other formulas:

Body Mass Index: kg/m2

Lean Body Weight: 

Ideal Body Weight: 


 for default units
( lbs/kg, in/cm) and calculation formula.


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BSA is a measurement used in many medical tasks.  Various Body Surface Area formulas have been developed over the years, originally by Dr.s  Du Bois & Du Bois,  followed by Gehan and George, Haycock, Boyd and Mosteller.  These formulas all give slightly different results.  It is probably not worth the trouble to debate about which formula may or may not be slightly better.  A bigger issue is lack of standardization. The Mosteller formula is gaining support as a common standard because it is much simpler and can be memorized and easily calculated with a hand-held calculator.

Dr DrHalls
Hi, and welcome. This was my first calculator and the first page on my website in 1999.


Some of you will feel nostalgia for the old BSA calculator, which fit better onto a standard computer monitor. But it looked quite old and I was forced to change the layout into a single column and make it responsive for use on cellphones.

I've used this redesign opportunity to show off my soft pastel colors style (which I made myself), and introduce the Moose.

Back in 1999, there was confusion about BSA and people were always looking up- and debating- the formulas. Nowadays the internet brings calculators like this to us instantly, and we just get our work done a little faster.

This calculator DOES HAVE some WEIRD behavior, if you enter weight or height values that are very large or small. It either shows error messages or changes the values. Way back in 1999 I thought that was a good safety check, but I'm having second thoughts now. I may remove or alter that to be less annoying.

On my Body Mass Index calculator, it has hover pop-ups for weight and height, so you don't have to type. I probably won't put that onto the BSA calculator, because it would encourage inaccurate rounding. But try it out and if you really want it on this page, let me know.


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June 22, 2019 by Dr. Halls

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