What is your Body Mass Index?

Body Mass Index (BMI) can be used to indicate if you are underweight, normal weight, overweight or obese.

BMI is an objective scientific measure, that uses your height and weight. You can calculate your BMI by dividing your weight in kilograms by the square of your height in meters (BMI = kg/m2), or simply use our handy BMI Calculator provided!

Calculate your Body Mass Index.

Body weight	Kilogrammes (kg) Pounds (lbs)
Enter your height	Metres Inches
Your Body Mass Index is:

BMI is not the same as Body Fat!

Two people can have the same BMI, but a different body fat percentage. For example, a bodybuilder with a large muscle mass and a low body fat may have the same BMI as a person who has more body fat - because BMI is calculated using weight and height only.

BMI should only be a guide and this is a good reminder that BMI is not the only indicator of someone’s health risk! BMI is just one of many factors related to developing chronic diseases such as heart disease, cancer, or diabetes. Other factors that may be important to look at when assessing your risk for chronic disease include:

• Diet
• Physical activity
• Waist circumference
• Blood pressure
• Blood sugar level
• Cholesterol level
• Family history of disease

Find out which weight category your BMI matches:-

If your BMI is below 18.5:
Low BMI, which can indicate that you may be underweight or have low body fat levels. In certain circumstances this can be desirable (e.g. an athlete). If your BMI and body weight are low, this may lower your immunity to disease so you should consider gaining increased muscle mass through a healthy diet and exercise program.

If your BMI is between 18.5 and 24.9:
A BMI in this range indicates a healthy normal weight and is associated with longevity (increase life expectancy) and a low incidence of serious illnesses. Studies have shown that this is the level that most people find aesthetically pleasing.

If your BMI is between 25 and 29.9:
BMI in this range is considered to be overweight, and having an increased risk of associated disease. Ideally if you are in this range you should consult your GP and discuss ways to lower your weight, change to a healthy diet and become more physically active.

If your BMI is between 30 and 39:
We have now reached the obesity range. It is essential that a lifestyle change is undertaken for health reasons. Changing to a healthy diet and regular exercise program is essential. If an individual is in this range with a waist size of 40 inches or more (men) or 35 inches or more (women) then there is a very high associated risk of disease.

If your BMI is over 40:
This indicates an individual suffering from extreme obesity, and is in a very unhealthy condition. The excess body fat will put the individual at risk of heart disease, diabetes, high blood pressure, gall bladder disease and some cancers. It is definitely time to seek medical advice urgently.

NB - There are two different ranges for healthy BMI put forward by different, but respected, sources. The British Nutrition Foundation, for example, gives 20-25 as healthy range and less than 20 as underweight. The Food Standards Agency's BMI calculator gives 18.5-25 as healthy and less than 18.5 as underweight. Cancer Research UK gives both ranges in different sections of its website. It seems that we can be a bit relaxed about a BMI of between 18.5 and 20, and not start worrying about being underweight unless BMI is less than 18.5. Having said that, we would not recommend that anybody with a current BMI of less than 20 should try to lose weight.

Need to lose weight?

ADVICE:
If you have any concerns about your weight contact your GP.

REMEMBER:
If you need to lower your BMI do it gradually overtime, don't starve yourself or over-exert your body with strenuous exercise.

TIP:You can experiment with our BMI calculator to see how much weight you need to lose to get your BMI down.

All content within this BMI section is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other health care professional. Always consult your own GP if you're in any way concerned about your health.