The Body Mass Index (BMI) is a tool that can be used to tell how healthy a person's weight is. You can use the BMI to find out if you're a healthy weight for your height.

If you know your height and weight, you can work out which weight range you're in using the simple steps outlined below.

- Take your weight in kilograms (kg) and divide it by your height in metres (m).
- Then divide the result by your height in metres (m) again.

For example, if you weigh 70kg, and you're 1.75m tall, your BMI would be 22.9 (70/1.75 = 40 and 40/1.75 = 22.9).
BMI calculator

Alternatively, use our BMI calculator. Simply enter your height, weight and sex to find out your BMI. See the 'further information' section for a link to the BMI calculator.

The BMI weight ranges, as set out by the World Health Organisation (WHO), are outlined below.

- If your BMI is less than 18.4, you're underweight for your height.
- If your BMI is between 18.5 and 24.9, you're an ideal weight for your height.
- If your BMI is between 25 and 29.9, you're over the ideal weight for your height.
- If your BMI is between 30 and 39.9, you're obese.
- If your BMI is over 40, you're very obese.

If you have a BMI of over 25, you need to think about losing weight because you have an increased risk of developing serious health problems, such as heart disease, diabetes, and several forms of cancer.

If your BMI is over 30, you need to make some immediate changes to your lifestyle in order to lose weight.

Treat Discreet provide a range of Weight Loss products:
- Adios
- Alli
- Appestat
- Formoline, and
- Lipobind

Obesity causes 9,000 premature deaths in England every year, and on average reduces life expectancy by a whopping nine years. It's also linked to serious health problems including type 2 diabetes, heart disease and cancers of the breast, colon and prostate.

You can find a host of articles to help you with all aspects of attaining a healthy weight in the Lose Weight section of NHS Choices:

- See how you can cut back calories by making simple changes to your everyday diet in the article Healthy food swaps.  
- It’s not just small changes to your eating habits that can make a big difference. Getting more exercise also helps you to shed the pounds, and you can do it in just three 10-minute-a-day bursts with these Ten-minute workouts. 
- Even if you're well on the way towards your target weight, there are always danger zones that leave you tempted to overindulge. See our tips on how to avoid the Diet danger zones. 
- One excuse for choosing a fat-laden quick-fix supper is that healthy eating is expensive, but don’t be fooled. See how to save pennies as well as calories in Eat well on the cheap. 
- Two-thirds of dieters regain all the weight they've lost within four years. For advice on how to stop piling back on the pounds read Lose weight for life.