Body Mass Index

Body Mass Index (BMI) is a number calculated from a person’s weight and height. BMI provides a reliable indicator of body fatness for most people and is used to screen for weight categories that may lead to health problems.

How is BMI used?

BMI is used as a screening tool to identify possible weight problems for adults. However, BMI is not a diagnostic tool. For example, a person may have a high BMI. However, to determine if excess weight is a health risk, a healthcare provider would need to perform further assessments. These assessments might include skinfold thickness measurements, evaluations of diet, physical activity, family history, and other appropriate health screenings.

Calculation of BMI

Formula: weight (kg) / [height (m)]²

With the metric calculation, the formula for BMI is weight in kilograms divided by height in meters squared. Since height is commonly measured in centimeters, divide height in centimeters by 100 to obtain height in meters.

Example: Weight = 68 kg, Height = 165 cm (1.65 m)
Calculation: 68 ÷ (1.65)² = 24.98

Or use the imperial calculation :

Formula: weight (lb) / [height (in)]² x 703

Calculate BMI by dividing weight in pounds (lbs) by height in inches (in) squared and multiplying by a conversion factor of 703.

Example: Weight = 150 lbs, Height = 5′5″ (65″)
Calculation: [150 ÷ (65)²] x 703 = 24.96

Or simply enter your weight and height in the provided BMI calculater on this site, you can find it in the right side bar.

• If your BMI is less than 18.4, you’re underweight for your height.
• If your BMI is between 18.5 and 24.9, you’re an ideal weight for your height.
• If your BMI is between 25 and 29.9, you’re over the ideal weight for your height.
• If your BMI is between 30 and 39.9, you’re obese.
• If your BMI is over 40, you’re very obese.

If you have a BMI of over 25, you need to think about losing weight because you have an increased risk of developing serious health problems, such as heart disease, diabetes, and several forms of cancer.

If your BMI is over 30, you need to make some immediate changes to your lifestyle in order to lose weight.

Notes:

• This is general advice for adults only – it doesn’t apply to children.
• When you work out your BMI, remember to take into account your body frame and your build – your BMI may not be accurate. For example, your BMI may not be accurate if you’re a weight-trainer, an athlete, or if you’re pregnant, or breastfeeding.
• Your BMI may not be accurate if you’re over the age of 60. This is because your bones may begin to weigh less as you get older.