Body Mass Index (BMI) is a measure of body weight based on a persons' height and weight and can be obtained by using a statistical equation and without the expenses of analysis machines to measure a healthy body weight. Recognize the fact that I stated BMI is a measure or body weight and not body fat. BMI is a widely used equation to measure a healthy body weight and identify people who are at risk of disease because of their BMI numbers. The population of people that can skew these numbers are those with plenty of lean body mass including athletes and bodybuilders.
Our body mass index is calculated by taking our body weight in kilograms and dividing it by the square of our height in meters.
BMI = mass (kg) / height (m)2
It is known that there is 2.2 kg in 1 lb. So to convert pounds in kilograms we need to divide our weight by 2.2. For example
220 lb person weight in kilograms = 220/2.2 = 100 kg
It is also known that there is 2.54 cm in 1 inch. We need to take our height in inches and multiply it by 2.54. For example if we are 6'1 (6 foot 1 inches) that is 6 ft x 12 inches = 73 inches + 1 more inch (since we are 6'1) = 74 inches.
Take that 74 inches and multiply it by 2.54 cm.
74 x 2.54 =187.96 centimeters (cm).
But we are not done yet. The next part is converting centimeters into a meter. Since 1 meter is equal to 100 centimeters we need to divide our above answer by 100.
187.96 cm/100 = 1.88 meters (m)
We now can plug these numbers into our equation.
1.88 m2 or 1.88 x 1.88 = 3.53
100 kg / 3.53 m2 = 28.33
This number would classify the client as overweight according to their BMI.
Underweight = <18.5
This states that your weight based on your height may be too low and can cause health concerns. You should consult your physician about adding on healthy weight to boost immunity and overall health
Normal Weight = 18.5 - 24.9
This is a healthy weight and correlates with the lowest rate of sickness.
Overweight = 25-29.9
You need to find ways to lower your weight and evaluate your diet to decrease your potential risk for disease of stroke, high blood pressure, diabetes and many other health issues related to a high BMI.
Obesity = BMI of 30 or more
Your risk of heart disease, diabetes, and high blood pressure are at a dangerous risk with a BMI this high.
Once again I will state this is just a general formula used to assess healthy body weight. It should be used in conjunction with other measuring factors such as underwater weighing, skin fold measurements, and other tools to asses your current state of health and future prosperity.
If you want to take the easy way out you can find a chart online where you match up your height and weight such as the one posted here or you can find a website with a BMI calculator and all you do is plug in the numbers.