What is BMI? How do I calculate it? All your questions about BMI answered

Use this formula to calculate your BMI and refer to the BMI chart if you are trying to lose weight.

By: Tania Tarafdar | | Updated: June 8, 2015 8:12 am

BMI is a popular weight loss term thrown around with little explanation. If you are confused about what it means and how to calculate it, here is a brief by Althea Shah, Fitness Expert & VP Marketing, Gold’s Gym India to help you out. Also Read - 5 useful steps to jumpstart your workout routine for weight loss

Also Read - 6 possible causes of sudden weight gain that need attention right now

What is BMI? Also Read - Saliva can predict excess body fat in teenagers

BMI stands for Body Mass Index and is a useful measurement for most people over 18. It is a measurement derived from your weight and height that estimates your body composition. It tells you whether you are underweight, overweight or an ideal weight for your height.

Knowing your BMI is important as a high BMI can be an indicator of high body fat and the associated risks of carrying this extra weight. If it does not fall in the desired range, you face health risks like diabetes, stroke, high blood pressure, high LDL cholesterol, coronary heart disease and osteoarthritis.

How to calculate BMI?

Step 1: Weigh yourself.

Step 2: Write down your height in meters. To obtain height in meters, divide height in centimeters by 100

Step 3: Calculate your BMI using the formula: Weight in kilograms divided by the square of height in meters, i.e. weight (kg) / [height (m)]2

Example: Weight = 60 kg, Height = 166 cm (1.66 m)

Calculation: 60 (1.66)2 = 21.77

Interpretation

BMI less than 18.5: Underweight
BMI between 18.5 25: Healthy weight
BMI between 25 30: Overweight
BMI between 30 40: Obese
BMI over 40: Very obese

How accurate is BMI?

BMI differs for men and women and cannot be considered to be 100% accurate. It takes into account only two factors- your height and your weight and not your body fat content versus lean tissue (muscle) content. For instance, women tend to have more body fat than men at the same BMI. Similarly, at the same BMI older people, on average, tend to have more body fat than younger adults. Athletes have less body fat than non-athletes. Again, a 6 feet athlete may have a higher BMI than a couch potato of the same height – but the couch potato may be overweight while the athlete is not.

Is there another way to calculate a more accurate BMI?

To get a more accurate reading, you may opt for skinfold thickness measurements (with calipers), underwater weighing and bioelectrical impedance analysis. However, these methods are not readily available and are either expensive or conducted by highly trained personnel. You can also get your assessment at a reputed gym that has access to a Body Composition Analysis Machine.

Here is the BMI chart for healthy adults. (Pink = Obese, Yellow = Overweight, Green = Normal)