Calculating BMI

You might be wondering why your friend who weighs exactly same, looks thinner than you. You may look chubbier than your friend because you have different body mass indices. Body mass index is nothing but height to weight ratio that is considered as an important parameter in determining the excessive amount of mass in the human body. Calculating BMI is therefore essential before focusing on pounds and kilos. If you are worried about how to calculate BMI, here is the simple formula for calculating BMI.

How to Calculate BMI
In order to calculate body mass index, following formula is used:

• As per SI Units: BMI (in kg/m²) = mass (in kg)/(height in meters)²
• Imperial Units 1: BMI = mass (lb) × 703/(height (in))²
• Imperial Units 2: mass (lb) × 4.88/(height (ft))²

BMI is also referred to as 'Quetelet Index', after its inventor, Belgian polymath Adolphe Quetelet. BMI is the parameter used to compare a person's height and weight. Researchers have studied and established values for an ideal weight-height scale, which are used worldwide to determine, whether a person is underweight, overweight or within the range of ideal weight. Body mass index is directly proportional to weight of an individual and inversely proportional to square of the height. Here is an obesity chart which will help you determine whether you need to shed some pounds or not.

BMI Calculations and Obesity

Calculated BMI	Conclusion
BMI < 17.5	Extremely underweight
BMI < 18.5	Underweight
BMI 18.5 to 25	Normal or optimal weight
BMI > 25	Overweight
BMI = 30 or BMI > 30	Obese
BMI = 40 or BMI > 40	Morbid obesity

Women are always seen asking the question "am I overweight for my height". It should be borne in mind that procedure for calculating BMI for women and calculating BMI for men is exactly the same. BMI is a parameter which helps determine healthy weight for women and men as well. Both men and women may refer to the table above, before opting for weight loss diets. Those having a BMI between 18.5-25 should maintain their weight with the help of balanced diet and regular exercises. These days, advanced BMI calculators are available on various sites on net. You can just enter your weight and height in the given parameters and you get your BMI within a fraction of a second. To get more accurate answer, advanced calculators also include age and gender while calculating BMI. So, if the question, 'what should I weigh for my age and height' is swirling in your mind, then you can easily find out the answer with the help of advanced BMI calculators.

Calculating BMI for Children
Age and gender should be taken into consideration while evaluating children or while calculating child body mass index; because children grow very fast and the amount of body fat varies according to age and gender. Evaluating children on the basis of 'BMI-for-age percentile' is more correct. Though it is referred to as 'BMI-for-age', it is 'age- and sex-specific'. The percentile helps you know the relative position of the child's BMI number among children of the same sex and age. Parents who are worried due to childhood obesity may use BMI to determine whether their children are obese or not.

Calculating BMI is actually too generalized and may not be suitable for everyone. Body builders or a person having significant muscle mass will have a comparatively higher BMI but it would be wrong to consider him as overweight because muscle weighs more than fat. So, before concluding about being overweight, you should always consult your physician.