# BMI Calculator Explanation

Body Mass Index, commonly known as BMI, is a numerical value that is used to assess the health and wellbeing of an individual. BMI is calculated by dividing an individual’s weight in kilograms by their height in meters squared. The resulting value is then compared to standard ranges to determine whether the individual is underweight, normal weight, overweight, or obese.

## How BMI Calculator

BMI is a useful tool for health professionals to assess the risk of developing health problems related to excess weight, such as heart disease, diabetes, and certain types of cancer. It is important to note that BMI is just one of several factors that health professionals use to assess overall health and that it is not a perfect measure of health status.

# BMI healthy weight calculator

The body mass index (BMI) is a measure that uses your height and weight to work out if your weight is healthy.

### Important:Changes to the BMI healthy weight calculator

The BMI healthy weight calculator is being updated and is temporarily unavailable.

If you’re concerned about your weight, or the weight of someone you care for, speak to a GP.

The BMI calculation divides an adult’s weight in kilograms (kg) by their height in metres (m) squared.

For example, an adult who weighs 70 kg (around 11 stone) and whose height is 1.75 m will have a BMI of 22.9.

## Limitations of the BMI

The BMI calculation is not suitable if you:

• have an eating disorder – please get further advice from a GP.
• are pregnant – your BMI will go up as your weight increases during pregnancy. Use your pre-pregnancy weight when calculating your BMI.
• are under 18 years old – children and young people’s weight is measured in centiles based on an average from national surveys. If you’re concerned about your child’s weight, see a GP.

## Black, Asian and ethnic minority groups

Black, Asian and other minority ethnic groups have a higher risk of developing some long-term conditions, such as type 2 diabetes.

People from these groups with a BMI of:

• 23 or more are at increased risk
• 27.5 or more are at high risk

### Muscle mass

The BMI calculation does not include muscle mass, which weighs more than fat.

This means muscular adults and athletes may be classed as overweight or obese even though their body fat is low.

Adults who lose muscle as they get older may fall into the healthy weight range even though they may be carrying excess fat.

## BMI weight ranges

### Underweight

Being underweight could be a sign you’re not eating enough or you may be ill. If you’re underweight, a GP can help.

### Healthy weight

Find out more about having a balanced diet and find fitness videos you can try at home to maintain a healthy weight.

### Overweight

If you want to lose weight, you can find more information at NHS Better Health.

## Waist to height ratio

Measuring your waist to height ratio can tell you if you have excess tummy fat, even if you have a healthy BMI.

To calculate your waist to height ratio, measure your waist and divide it by your height. Use measurements in the same units (for example, centimetres or inches).

A waist to height ratio of 0.5 or higher means you may have increased health risks such as heart disease, type 2 diabetes and stroke.

1. Find the bottom of your ribs and the top of your hips (just above your belly button).
2. Wrap a tape measure around your waist midway between these points.
3. Breathe out naturally before taking the measurement.

## BMI calculation formula

The formula for calculating BMI is relatively simple. An individual’s weight in kilograms is divided by their height in meters squared. The resulting value is then compared to standard ranges to determine whether the individual is underweight, normal weight, overweight, or obese.

BMI = weight (kg) / height² (m²)

For example, if an individual weighs 70 kilograms and is 1.8 meters tall, their BMI would be calculated as follows:

BMI = 70 / (1.8 × 1.8) BMI = 70 / 3.24 BMI = 21.6

## BMI ranges

The World Health Organization (WHO) has established standard BMI ranges to assess the health status of individuals. The following BMI ranges are generally accepted as standard:

• Underweight: BMI less than 18.5
• Normal weight: BMI between 18.5 and 24.9
• Overweight: BMI between 25 and 29.9
• Obese: BMI of 30 or higher

It is important to note that these ranges are general guidelines and that the ideal BMI may vary depending on an individual’s age, sex, and ethnicity.

BMI is a simple and effective tool that can be used to assess the risk of developing health problems related to excess weight. The following are some advantages of using BMI:

• Easy to calculate: BMI is easy to calculate and does not require any special equipment or tools.
• Inexpensive: BMI does not require any expensive tests or procedures and can be calculated using readily available information such as height and weight.
• Widely accepted: BMI is a widely accepted measure of body weight and is used by health professionals around the world.
• Risk assessment: BMI can be used to assess the risk of developing health problems related to excess weight, such as heart disease, diabetes, and certain types of cancer.
• Health promotion: BMI can be used as a tool to promote healthy lifestyles and encourage individuals to maintain a healthy weight.

## Limitations of BMI

While BMI is a useful tool for assessing the risk of developing health problems related to excess weight, it is important to note that it has some limitations. The following are some limitations of BMI:

• Not a perfect measure: BMI is not a perfect measure of health status and does not take into account factors such as muscle mass, bone density, and body composition.
• May overestimate risk in athletes: BMI may overestimate the risk of developing health problems in athletes and individuals with high levels of muscle mass.
• May underestimate risk in older adults: BMI may underestimate the risk of developing health problems in older adults and individuals with low levels of muscle mass.
• Does not distinguish between types of fat: BMI does not distinguish between visceral fat (fat around organs) and subcutaneous fat (fat under the skin), which can have different health implications.
• Ethnic differences: BMI may not be an accurate measure of health status for individuals from different ethnic backgrounds.

## BMI calculator

BMI calculators are readily available online and can be used to calculate an individual’s BMI quickly and easily. MostB MI calculators use the same formula for calculating BMI as mentioned above. However, the calculators provide an easy-to-use interface that requires the user to input their weight and height information, and the calculator automatically calculates and displays the BMI value. Some calculators may also include additional information such as BMI ranges, interpretation of results, and tips for maintaining a healthy weight.

There are several websites that offer free BMI calculators, and many health organizations and medical facilities have BMI calculators available on their websites. These calculators can be a useful tool for individuals who want to monitor their weight and assess their risk of developing health problems related to excess weight.

## Tips for maintaining a healthy weight

Maintaining a healthy weight is an important factor in overall health and wellbeing. The following are some tips for maintaining a healthy weight:

1. Eat a balanced diet: A balanced diet that includes a variety of fruits, vegetables, whole grains, lean proteins, and healthy fats can help maintain a healthy weight.
2. Exercise regularly: Regular exercise can help burn calories and maintain muscle mass, which can help maintain a healthy weight.
3. Get enough sleep: Getting enough sleep can help regulate hormones that control appetite and metabolism, which can help maintain a healthy weight.
4. Reduce stress: Chronic stress can lead to overeating and weight gain. Finding ways to reduce stress, such as through exercise, meditation, or therapy, can help maintain a healthy weight.
5. Avoid unhealthy habits: Avoiding unhealthy habits such as smoking, excessive alcohol consumption, and overeating can help maintain a healthy weight.

## Conclusion

BMI is a useful tool for assessing the risk of developing health problems related to excess weight. While it has some limitations, BMI calculators are readily available online and can be used to calculate an individual’s BMI quickly and easily. Maintaining a healthy weight through a balanced diet, regular exercise, and healthy habits is an important factor in overall health and wellbeing. BMI can be a useful tool for promoting healthy lifestyles and encouraging individuals to maintain a healthy weight.