BMI Information *

What is the BMI?

It is the abbreviation for the body mass index
It determines if your weight is healthy by comparing it to your height
It is measured by dividing your weight in kilograms by your height in metres squared
For example, a BMI of 25 means 25kg/m2

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What are the ranges?

For most adults, an ideal BMI is in the 18.5 to 24.9 range
For children and young people aged 2 to 18, the BMI calculation takes into account age and gender as well as height and weight
If your BMI is:
- below 18.5 – you're in the underweight range
- between 18.5 and 24.9 – you're in the healthy weight range
- between 25 and 29.9 – you're in the overweight range
- between 30 and 39.9 – you're in the obese range

How reliable are the results?

BMI takes into account natural variations in body shape, giving a healthy weight range for a particular height
As well as measuring your BMI, healthcare professionals may take other factors into account when assessing if you're a healthy weight
Muscle is much denser than fat, so very muscular people, such as heavyweight boxers, weight trainers and athletes, may be a healthy weight even though their BMI is classed as obese
Your ethnic group can also affect your risk of some health conditions. For example, adults of Asian origin may have a higher risk of health problems at BMI levels below 25. The current BMI calibrations are made on the Caucasian body-type and therefore may not be quite accurate for other ethnicities
Results for many elderly people may be inaccurate because of their loss of muscle mass
You should not use BMI as a measure if you're pregnant. Get advice from your midwife or GP if you're concerned about your weight