Body Mass Index Calculator

The Body Mass Index (BMI) is practical indicator of the risk of being overweight/ or obese by measuring your weight in relation to your height. The globally accepted BMI classification for adults is used by the World Health Organisation and this system is based on the relationship between your BMI, and the likelihood of premature mortality and chronic disease. The BMI Standards are age and gender independent and are worked out through this simple equation.


Weight in kilograms (kg) divided by height in meters squared (m2) = BMI (kg/m2).


What are the limitations of using BMI alone?

Although the BMI is a good marker for being overweight, the relationship between BMI and body fat can be skewed by large inter-individual variation such as muscle mass which weighs more than fat. Therefore, a second body composition measurement is highly recommended in addition to the BMI such as a waist circumference measurement.


How is a waist circumference measurement a predictor of health?

Studies on health has demonstrated that it is not just about how much fat an individual has on their body (although this is clearly important), but where this fat is located. Central obesity poses a major threat to health; in particular the amount of intra-abdominal fat (or visceral fat) that is stored within the visceral organs.

A simple WC measurement shows a strong correlation to the amount of fat stored within the visceral organs. Considerable amounts of published evidence show how excess weight around the waist area is an accurate predictor of a whole host of increased health problems, including Type 2 diabetes and cardiovascular disease.

Why is this?

Unfortunately, excess weight around the tummy/ abdominal area is known as visceral fat and due to the close proximity of the internal organs such as the liver, kidneys and pancreas reacts in a different and more harmful way than fat stored elsewhere in the body. This fat is far more metabolically active than fat elsewhere and has been termed ‘toxic fat’.

The pear shapedfat around the hips and thighs does not appear to operate in the same way and is relatively inactive and inert. Too much fat around the waist can affect the way in which insulin is used, which in turn raises blood pressure and increases the amount of cholesterol in the body. Abdominal fat cells can quickly break down stored fats. It then dumps the resulting fatty acids into the bloodstream that can cause high levels of fat and sugar in the blood, thus increasing your risk of diabetes (in the case of excess sugars) and heart disease (in case of fats).

What Waist Circumference measurement is defined as ‘at risk’?

The American College of Sports Medicine (ACSM) has published recommended guidelines, indicating low/elevated/increased health risk by size of your Waist Circumference. The most commonly used cut off points in men are 94 cm (37 inch) or greater, which denotes a moderately increased risk of obesity related complications, and a Waist Circumference of 102 cm (40 inch) or greater, which denotes a substantial increased risk of obesity related complications. The corresponding Waist Circumference thresholds for women are 80 (32 inch) and 88 cm (35 inch) respectively. To find out your Body Mass Index enter your weight in pounds or kilograms and your height in inches or cmd and click calculate.  Once you have your BMI number check your health risk by looking at the charts below.


Risk of Associated Disease According to BMI and Waist Size

BMI (Body Mass Index)


Waist less than or equal to 40 in. (men) or 35 in. (women)

Waist greater than 40 in. (men) or 35 in. (women

18.5 or less


18.5 – 24.9


25.0 – 29.9



30.0 – 34.9



Very High

35.0 – 39.9

Very Obese

Very High

Very High
40 or Greater Extremely Obese Extremely High Extremely High


A Visual Chart To Check BMI & Health Risk

bmi chart