BMI Calculator

The BMI (body mass index) is a measure of whether you're a healthy weightfor your height. Utilize the BMI calculator to determine for the parents in your home.

For children, visit Weight Concern's Child page and the young people's Body Mass Index (BMI) calculation calculator. Imperial

This calculator is only to be only used only by adult users (pregnant or lactating mothers should not be relying on the BMI readings) And no action should be taken based on its values aside from consulting the appropriate person, such as a physician.

The calculator will give you an the information you need to know what your weight is in relation to common values. Body Mass Index (or BMI) is calculated by taking your weight (in kilograms) per square of height (in metres) or BMI = Kg/M2.

Is Body Mass Index reliable?

Your BMI is also known as Body Mass Index, is a measure of your weight in relation to your height. It is crucial to make accurate assessments of obesity. essential as being obese or overweight significantly increases your risk of a range of health conditions, including type 2 diabetes, heart disease and cancer. With the rate of weight gain or obesity rise and the focus has been upon BMI and its shortcomings as a measure of ideal weight for an individual instead of a whole population of people for whom "averages" are used.

"Some people naturally have a larger frame than others. But this causes quite a small variation in weight and is accounted for in the range of healthy BMI. There is really no such thing as someone who is big-boned. " Dr Jan Sambrook, How to lose weight in a healthy way

For most adult people, BMI provides a reliable assessment of your weight-related health risk. If your BMI is greater than 35, you are certainly putting your health at risk regardless of the risk factors below. However, there are a few instances where BMI can underestimate or overestimate these risks in the 25-35 BMI range. The main ones are:

Children

Your physician or health visitor can guide you on what your child's position is on the 'centile charts' used to estimate the weights that are healthy for children.

Pregnant women

Usual BMI estimates do not apply if you're pregnant.

If you're very muscular

BMI assumes you have equal amounts of body fat, including 'intra-abdominal fat' - belly fat that's located deep in your cavity, not under your skin. Fat in the abdominal area is more strongly linked to the risk of type 2 diabetes and heart disease than fat beneath the skin.

If you are very muscular then your body fat may be lower than predicted by your BMI. But, this is only applicable to those who engage in intense exercise higher than average.

If you're of Asian origin

People who are of Asian heritage are more susceptible to develop abdominal fat (fat in your stomach cavity and not under your skin) with lower BMIs than those of Caucasian origin. People who suffer from this pattern for weight increase are referred to as 'apples' , rather than "pears" in their body outline. It means that their health risk are increased at lower BMI due to the fact that abdominal fat is directly linked to the development of heart disease and type 2 diabetes.

The World Health Organisation has looked at the evidence and because there is a wide variation between Asian populations and the different ethnic groups, it hasn't made any changes to the cut-off points. However, it has recommended that for health reasons there are certain Asian groups are considered overweight with a BMI of 22-25, and obese with BMIs of 26-31.

People who are older (over 65, or possibly 60)

Since muscle mass tends to decrease and body fat tends to rise in older people It is possible that BMI is not an accurate indicator of body fat levels if you're over 60.

Alternative estimates of health-related weight risk

If you believe that BMI does not accurately determine if you're obese or overweight by measuring your abdomen circumference, waist-hip or waist ratio may give you a more realistic estimate.

Waist circumference

Your waist circumference should be measured half way between the bottom of your ribcage and high-top of your hip bones, using a tape measure that is in line with the floor. The person breathing out must be present as you measure. Male

• Risk of increased health - >=94cm
• High risk of health - > 102cm

Female

• Risk of increased health - >80cm
• High risk of health-related illness - >=88cm

The ratio of waist to hip

To determine your waist to hip ratio, take a measurement of your waist's circumference (as above), and your hip size at the widest part of your hips. Divide your abdominal circumference in relation to your hip measurement to give an approximate ratio.

• For women, a waist to hip ratio that is greater that 0.85 is associated with higher than average risk.
• In males, a waist to hip ratio that is greater than 1.00 is associated with a greater than the average risk.

Ratio of waist to height

A study conducted recently comparing BMI, waist circumference, waist to hip ratio and the ratio of waist to height discovered that the most reliable method of determining your fat level was waist-height ratio.

The waist circumference should be measured as above, and then divide it by height. pretty obvious that both measurements should soit be measured in imperial (inches) or metric (cm).

The definition of obesity for the whole body is by a waist-to-height ratio of:

• 0.53 or more for males
• 0.54 and more in women

Abdominal obesity is defined as an waist-to-height ratio of 0.59 or more.

Are you protected against flu? Check now