BMI Calculator - Optimum Wellness

Introduction to the body mass index (BMI)
Body Mass Index (BMI) is widely used as an indicator of body fat content. Your weight alone is not sufficient to establish if you are in a healthy weight range. For example, a tall but slender person can weigh more than a short but plump individual. But the former may enjoy better health as long as their weight is suitable for their height. The ideal weight is also likely to differ for men and women of similar heights.

How then do you know whether you fall in the healthy weight range or not? Your BMI solves this confusion. It correlates your weight with your height and evaluates whether your weight is appropriate for your stature. You can use a BMI calculator to find out your BMI.

Although not an exact measurement of body fat percentage, in most cases, BMI is a reliable tool for establishing risk levels for illnesses, especially ailments related to excess body fat. Many healthcare professionals use BMI to determine effective doses for medicines. Often people with a higher BMI need higher doses. Hence, it is crucial to be aware of your BMI to ensure your overall wellness.
How to calculate BMI
If you want to calculate your BMI, you have to find out your weight and height first. Once you know these values, you can arrive at the result by following the two steps mentioned below:
1. Multiply your height by itself (height X height).
2. Divide your weight by the answer you get in the first step.
The equations for calculating the BMI are as follows:
International System of Units (SI)
BMI = weight (kg) ÷ (height (m))2
For a 177 cm (1.77 m) individual weighing 75 kg,
BMI = 75 / (1.77 * 1.77) = 75/ 3.13 = 23.96
Imperial System
BMI = weight (lb) ÷ (height (inches)) 2 × 703
For a 160-pound, 5’8” (68”) individual weighing 75 kg,
BMI = (160/ 68*68) * 703 = (160/4624) * 703 = 24.3
You can also use an online BMI calculator to find out your BMI and eliminate human errors.
Potential drawbacks of BMI as a measure of body composition
  • Muscle mass - Since BMI is only based on your height and weight, it is too simplistic a measure to determine your health. It does not take into account how much of your weight is muscle mass. When you have more muscle, your BMI will be higher, even if you are fit and healthy.
  • Bone density - Some people have denser bones and larger frames than others. However, people with large frames will have higher BMIs, even though they may be healthy and not overweight.
  • Age - Even if body weight remains constant, aging causes considerable changes in body composition, including a significant decrease in muscle mass and an increase in visceral fat. Visceral fat is more dangerous, but BMI does not use this factor in its calculation.
  • Sex - Studies in the past found that women had a higher prevalence of obesity than men, especially women over 50. Visceral or subcutaneous fat gain is linked to fat accumulation, which increases body mass. These changes differ in men and women because aging women experience a redistribution of abdominal fat.

    However, this physiological difference in body fat percentage between males and females is not properly measured by BMI.
  • Ethnicity - Aside from age and gender, large ethnic variations in body composition have been found. Individuals from certain ethnic backgrounds may have a higher BMI but still may be healthy due to higher non-fat mass.

    In addition to fat distribution, hypertension risk, and type II diabetes risk, there are also disparities in muscularity, bone mass, and leg length among different ethnicities. This increases the ethnic-specific connections between body fat and BMI.

    These ethnic disparities in body fat are the result of genetically determined differences in body composition and metabolism, as well as a variety of risk factors caused by social and environmental factors.
  • Self reported data - Because of the lower costs and ease of fieldwork, nutritional epidemiology mainly depends on self-reported data to measure health. However, the credibility of self-reported data is questionable. The same is true for BMI.

    According to many studies, body weight is strongly under-reported and height is significantly over-reported, with severe miscalculations of BMI categories. Miscalculation of the various BMI categories can obscure the underlying links that exist between obesity and chronic health conditions, such as heart disease, asthma, diabetes, high blood pressure and sleep disturbances.
What are the limitations of BMI in children?
The same concerns about using BMI to measure body fat in adults apply to children and adolescents. In children, other factors such as puberty change the link between BMI and body fat.

While BMI may still be a good predictor of excess body fat in obese children, elevated BMI levels in overweight children can be caused by an increase in either fat or non-fat mass. Similarly, disparities in BMI among relatively thin children are often related to differences in fat-free mass.