Body Mass Index (BMI)

Calculating adult weight with BMI

Body Mass Index (BMI) is calculated by dividing your weight (in kilograms) by your height (in metres) squared. The standard weight status categories for different BMI ranges for adults are shown in the table below.

While BMI provides a good estimate of body fat for most people, it may not be suitable for some groups such as athletes who have a muscular build, older people, and some ethnic groups. 

BMI	Classification
Below 18.5	Underweight
18.5 – 24.9	Healthy weight range
25.0 – 29.9	Overweight
30 and above	Obese

Use the LiveLighter BMI calculator tool (external site) for an easy way to calculate your own BMI.

Measure your waist circumference for adults

Measuring your waist circumference is a simple way to assess your risk of developing obesity-related health conditions. Excess fat around your waist is known to be more dangerous to your health than excess fat in other places on your body, for example on your hips and thighs.

To measure your waist circumference:

1. Find the top of your hip bone and the bottom of your ribs.
2. Breathe out normally.
3. Place the tape measure at the narrowest part between these points and wrap it around your waist.

The table below shows your disease risk based on your weight circumference.

Waist circumference	Disease risk
Men less than 94cm Women less than 80cm	Low risk
Men between 94 – 102cm Women between 80  –  88cm	Increased risk, especially if your BMI is more than 25
Men more than 102cm Women more than 88cm	Substantially increased risk

Where to get help

• If you have concerns about your weight talk to your doctor.
• For information about the amount and types of food you should be eating for health and wellbeing visit the Eat for Health website (external site).
• For tools and tips to help you make positive changes to your lifestyle visit the LiveLighter website (external site).

Remember

• BMI provides a good estimate of body fat for most people.
• Waist circumference is a simple way to assess your risk of developing obesity-related health conditions.

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This publication is provided for education and information purposes only. It is not a substitute for professional medical care. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your healthcare professional. Readers should note that over time currency and completeness of the information may change. All users should seek advice from a qualified healthcare professional for a diagnosis and answers to their medical questions.