Living with Diabetes

Body Mass Indicator (BMI)

Are you overweight?

Your ideal body weight depends on your height and whether you are male or female. Your waist size also gives a rough idea - the longer the distance around your tummy the  greater the risk to your health!

What is BMI?

BMI is a number derived from a formula using your weight and height. It is a useful way of finding out whether your weight is suitable for your height. BMI is a more useful number to interpret than your weight when assessing your health risk.

How is it calculated?

You can calculate your body mass index using this formula:

BMI =  Weight in kilograms / (Height in meters)2

For example, if you are 6ft tall (1.83 metres) and 12 stone (75.3 Kilograms) in weight, then your BMI is as follows:

BMI = 75.3 / 1.832 = 22.48

Alternatively, use the BMI Calculator below.

How do I interpret this number?

A body mass index greater than 27 kg/m2 suggests that you are overweight and a BMI over 30 kg/m2 indicates obesity.


BMI - Women

BMI -Men


Less than 19.1

Less than 20.7

Ideal weight

19.1 to 25.8

20.7 to 26.4

Marginally overweight

25.8 to 27.3

26.4 to 27.8


27.3 to 32.2

27.8 to 31.1

Very overweight or obese

32.3 to 44.8

31.1 to 45.4

Extremely obese

More than 44.8

More than 45.4

(Source: Understanding Nutrition by Whitney and Rolfes)

Body Mass Index (BMI) Calculator

The form below allows you to calculate your BMI using imperial units. Simply select your nearest height (in feet and inches) and weight (in stones and pounds) from the drop down boxes and click the 'calculate' button.

BMI Calculator (imperial):





The form below allows you to calculate your BMI in metric units. Enter your height in metres, then enter your weight in kilograms and click the 'calculate' button.

For example, your height might be 1.83 (about 6 feet) and your weight might be 76.2 (about 12 stone).

BMI Calculator (metric):






Dr. Nishan Wijenaike, Consultant Physician
West Suffolk Hospital Diabetes Service
October 2002