What is The Body Mass Index (BMI)?

Your body mass index (BMI) is a step which uses your height and weight to workout if your weight is healthy.

The BMI calculation divides an adult’s weight in kilograms by their height in metres squared. As an instance, A BMI of 25 signifies 25kg/m2.


BMI Ranges

For many adults, an perfect BMI is at the 18.5 to 24.9 range.

For children and young people aged 2 to 18, the BMI calculation accounts for age and sex in addition to weight and height.

If your BMI is:

  • Under 18.5 — you are at the underweight selection
  • Between 18.5 and 24.9 — you are at the healthy weight range
  • Between 25 and 29.9 — you are in the obese variety
  • Between 30 and 39.9 — you are in the fat selection



Accuracy of BMI

BMI takes into account natural variations in body contour, providing a healthy weight range for a specific height.

In addition to quantifying your BMI, caregivers may take different factors into consideration when assessing if you are a healthy weightloss.

Muscle is a lot denser than fat, therefore very muscular individuals, like heavyweight boxers, weight trainers and athletes, might be a healthful weight although their BMI is known as overweight.

Your cultural group may also impact your risk of several health states. By way of instance, adults of Asian source might have a greater risk of medical issues in BMI levels under 25.

You shouldn’t use BMI as a step if you are pregnant. Get information from your midwife or GP if you are worried about your weight.


How Do I Work Out My BMI?

To work out your BMI:

  • divide your weight in kilograms (kg) by your height in metres (m)
  • Then divide the solution by your height to receive your BMI

For example:

  • Should you consider 70kg and you are 1.75m tall, then divide 70 by 1.75 — that the response is 40
  • Then split 40 from 1.75 — that the response is 22.9
  • your BMI is 22.9kg/m2


Charts and Online Calculators

Charts and tables, like the one below, are just one easy way to work out your BMI. Additionally, there are a number of online BMI calculators, like this one on our site.

To use the table below, locate your height on the left side of this graph, then move around to the weight that’s nearest to yours. At the Peak of the graph you can see your BMI, and also in the bottom of the graph you can determine that category you fit right into — healthy weight, overweight, or fat:



Calculating my BMI

You can even calculate your own BMI.

The actual formula to determine BMI uses metric system measurements: weight in kilograms (kg) divided by height in meters, squared (m2).

BMI = (your weight in kg) ÷ (your height in meter x your height in meter)

When using inches and pounds, the formula has to be shifted slightly.

Multiply your weight in pounds by 703. Divide that by your height in inches, squared:

BMI = (your weight in pounds x 703) ÷ (your height in inches x your height in inches)

As an instance, if you weigh 120 lbs and are 5 ft. 3 in. (63 in.) Tall:

BMI = (120 x 703) ÷ (63 x 63) or 84,360 ÷ 3969 = 21.3

That is well within the healthy weight range.


Are There Any Issues Using the BMI?

Physicians and physicians often use BMI to help determine if someone may have a weight issue. BMI provides a fantastic estimate of overall body fat for most individuals, but it does not work well for everyone. By way of instance, bodybuilders or other very muscular individuals may have a higher BMI due to their muscle mass, despite the fact that they’re not always obese. The BMI also can underestimate body fat in those who have lost muscle mass, for example a few elderly folks.

For many adults, the BMI is a fantastic method to get an notion of healthy weight ranges. Nevertheless, it is not necessarily the last word in determining if a individual is overweight or obese. You can find different things to think of when estimating just how much somebody must weigh. Someone who has a high BMI ought to be assessed by a healthcare provider, who may use different aspects like skinfold thickness (a measure of body fat), waist size, tests of diet and household health issues, along with other elements to discover if a individual’s weight may pose a health hazard.


BMI in Children and Teens

BMI can be calculated exactly the exact same way for kids and teens because it is for adults, but the numbers do not have exactly the exact same significance. That is because the standard quantity of body fat varies with age in children and adolescents, and differs between girls and boys. So for children, BMI amounts that specify being normal weight or obese are according to the child’s age and sex.

To account for this, the US Centers for Disease Control and Prevention (CDC) has developed age- and gender-specific expansion graphs. These graphs are utilized to interpret a BMI number to a percentile according to a child’s gender and age.

The percentiles are subsequently Utilized to Ascertain the different weight classes:

  • Underweight: less than the 5th percentile
  • Regular weight: 5th percentile to less than the 85th percentile
  • Overweight: 85th percentile to less than the 95th percentile
  • Obese: 95th percentile or greater