Body Mass Index calculation

body mass index calculation © Philippe Devanne Fotolia This Body Mass Index (BMI) calculator for adults will allow you to know if you are overweight, obese, underweight or normal.

Enter your height and your weight, your Body Mass Index (BMI) will be computed automatically.
You can also enter your height and target BMI, weight to reach will be reverted.

You can also enter your age and sex to know your Body Fat Percentage (BFP).
If you enter your height, age, sex and a target BFP then weight to reach will computed.

Height in centimetres cm
Weight in kilogram kg
Body Mass Index (BMI) in kg/m2
Age in years
Sex Male   Female
Body Fat Percentage(BFP) %



Please note that if you are overweight, you may have trouble when you do exercise (like you get breathless quickly when you climb stairs) but you don't have to get guilty because mortality rate for overweight person in 6 % less thant the ones normal.

Here are categories defined by World Health Organization (WHO) :
< 16.5Severely underweight
16.5 to 18.5Underweight
18.5 to 25Normal
25 to 30Overweight
30 to 35Moderately obese (Class I)
35 to 40Severely obese (Class II)
> 40Very severely obese (Class III)

Here, how French population is divided in 2012 :
<18.5 (Underweight)3.5%
18.5 to 24.9 (Normal)49.2%
25 to 29.9 (Overweight)32.3%
30 to 39.9 (Moderately or severe Obese)13.2%
> 40 (Very severely Obese)1.2%

Normal Body Fat Percentage (BFP) is 15 to 30 % for female and 10 to 25 % for male.
Here are typical ranges for the body fat rate :
Vital minimum10–13 %2-5 %
Athletic14–20 %6-13 %
Good shape21–24 %14-17 %
Medium25–31 %18-24 %
Obesity32 %+25 %+


Body Mass Index formula is only valid for adults aged 18 to 65 years old, excepted dwarf, giant, victims of amputation. Athletes can have a BMI over 25 without any risk because of heavy muscles.

Body Fat Percentage (BFP) is an estimation and is not valid especially for adults over 50 years old, kids below 2 years old, pregnant women or the ones breast feeding, persons with lots of muscles, high level athletes, giants, dwarf or victims of amputations.
A slightly different formula is used for children under 20 years old.

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