NHS Adult BMI Calculator

Calculate your Body Mass Index (BMI) using NHS guidelines for adults

Metric (kg, cm)

Imperial (st/lb, ft/in)

Age (18-120 years) Age must be between 18 and 120 years

Biological Sex

Male Female

This is used for a more accurate health assessment

Height (cm) Height must be between 100 and 250 cm

Weight (kg) Weight must be between 30 and 300 kg

Age (18-120 years) Age must be between 18 and 120 years

Biological Sex

Male Female

This is used for a more accurate health assessment

Height

Height must be between 3ft and 8ft

Weight

For pounds only, enter 0 in stones field

Weight must be between 4st 7lb and 47st 8lb

Your BMI Results

kg/m²

Underweight
<18.5

Healthy
18.5-24.9

Overweight
25-29.9

Obese
30-39.9

Severely Obese
>40

BMI Category:

What this means:

Weight range for your height:

Recommended daily calories:

Health advice:

Note: This calculator is based on NHS guidelines for adults. The results should be used as a guide only. For personalized advice, please consult a healthcare professional.

Understanding BMI

About BMI

Limitations

Health Impacts

Weight Management

Body Mass Index (BMI) is a measure of body fat based on height and weight. It applies to adult men and women, defined as those 18 years or older.

How BMI Is Calculated

The BMI formula is:

BMI = weight (kg) ÷ height² (m²)

For imperial measurements, the formula is:

BMI = (weight (lb) × 703) ÷ height² (in²)

BMI Categories

BMI Range	Category	Health Risk
Below 18.5	Underweight	Higher risk of nutritional deficiencies and weakened immune system
18.5 to 24.9	Healthy weight	Lower risk of health problems
25 to 29.9	Overweight	Increased risk of heart disease, stroke, and type 2 diabetes
30 to 34.9	Obesity class 1	High risk of health problems
35 to 39.9	Obesity class 2	Very high risk of health problems
40 and above	Obesity class 3	Extremely high risk of health problems

While BMI is useful for most adults, it does have limitations and may not be accurate for everyone.

BMI May Not Be Accurate For:

Athletes and muscular individuals: Muscle weighs more than fat, so those with high muscle mass may have a higher BMI despite having healthy body fat levels.
Older adults: As we age, we tend to lose muscle and gain fat, even while maintaining the same weight and BMI.
Pregnant or breastfeeding women: Weight changes during pregnancy and breastfeeding are normal and necessary.
Different ethnic groups: People from South Asian, Black, and some other minority ethnic groups may have higher health risks at lower BMI thresholds.

Additional Measurements

For a more comprehensive assessment, consider combining BMI with other measurements:

Waist circumference: Measures abdominal fat, which is linked to higher health risks.
Waist-to-hip ratio: The ratio between your waist and hip measurements.
Body fat percentage: Directly measures the proportion of fat in your body.

Your BMI can significantly impact your health. Both underweight and overweight conditions are associated with various health risks.

Health Risks of Being Underweight (BMI below 18.5)

Nutritional deficiencies
Weakened immune system
Osteoporosis and bone fractures
Fertility issues
Growth and development problems

Health Risks of Being Overweight (BMI 25-29.9)

Type 2 diabetes
High blood pressure
Heart disease and stroke
Certain types of cancer
Sleep apnea
Osteoarthritis

Health Risks of Obesity (BMI 30 and above)

All risks associated with being overweight, but at higher severity
Severely reduced quality of life
Depression and anxiety
Bodily pain and difficulty with physical functioning
Increased risk of severe illness from COVID-19

If your BMI indicates that you should gain or lose weight, it's important to do so safely and sustainably.

NHS Weight Loss Plan

The NHS recommends a safe, sustainable weight loss of 0.5kg to 1kg (1lb to 2lb) per week. The NHS Weight Loss Plan is a free 12-week diet and exercise program available as a mobile app or online.

Key components include:

Setting realistic goals
Eating a balanced diet with reduced calories
Regular physical activity
Behavior change techniques

Physical Activity Guidelines

The NHS recommends adults should:

Aim for at least 150 minutes of moderate intensity activity or 75 minutes of vigorous intensity activity per week
Perform strength exercises on 2 or more days per week
Break up long periods of sitting with light activity

For Underweight Adults

If you're underweight, try to:

Eat frequent, nutrient-dense meals
Include healthy, high-calorie foods like nuts, avocados, and whole grains
Consider adding smoothies or shakes between meals
Engage in strength training to build muscle
Consult a healthcare professional if you're struggling to gain weight

Adult BMI Calculator: Assess Your Health Using NHS Tools

What Is BMI and Why Is It Important for Adults?

Body Mass Index (BMI) is a calculation used to assess an individual’s weight relative to their height. For adults, BMI provides valuable insights into whether they are at a healthy weight, underweight, overweight, or obese. By calculating your BMI, you can evaluate your risk for health conditions such as heart disease, diabetes, and high blood pressure.

Tracking BMI regularly helps adults maintain a healthy weight, identify weight-related health risks, and make informed lifestyle choices. The NHS offers a BMI calculator specifically for adults, making it easy for individuals to assess their weight status and take appropriate action.

How the NHS BMI Calculator for Adults Works

Using the NHS BMI Calculator for Adults

The NHS BMI calculator for adults is a straightforward tool that requires the following information:

Weight: Enter your weight in kilograms (kg) or pounds (lbs).
Height: Enter your height in centimeters (cm) or feet and inches (ft/in).
Age: Provide your age to ensure the result is adjusted appropriately.

Once you input these details, the tool will calculate your BMI and present the result in accordance with standard BMI categories.

Available Units: Metric & Imperial

The NHS BMI calculator offers two options for entering your data:

Metric Units: Weight in kilograms and height in centimeters.
Imperial Units: Weight in pounds and height in feet and inches.

Both unit systems provide the same accurate results but offer flexibility for users based on preference.

What Does the BMI Result Mean for Adults?

Understanding Your BMI Categories

For adults, BMI is categorized into different ranges to help you understand where you stand in terms of healthy weight:

Underweight: BMI below 18.5
Healthy Weight: BMI between 18.5 and 24.9
Overweight: BMI between 25 and 29.9
Obese: BMI of 30 or higher

These categories are useful for assessing weight in relation to height and can be an indicator of health risks. For example, a BMI in the overweight or obese range increases the risk for developing chronic conditions, while being underweight may indicate the need for nutritional improvements.

Why Use the NHS BMI Calculator for Adults?

Benefits of Using the NHS BMI Calculator

The NHS BMI calculator for adults offers a range of advantages:

Accurate and Easy-to-Use: The tool provides quick and reliable BMI calculations based on your weight and height.
Health Insights: It helps you understand whether you are at risk for certain health conditions such as diabetes, heart disease, and stroke.
Monitor Your Progress: By tracking your BMI over time, you can monitor your weight and make adjustments to your lifestyle, diet, and exercise routine.
Free and Accessible: The NHS BMI calculator is free to use and available online, making it easily accessible to anyone looking to monitor their weight.

How to Use the NHS BMI Calculator for Adults

Step-by-Step Guide to Using the BMI Calculator

Enter Your Information: Input your weight, height, and age into the calculator. You can choose between metric or imperial units.
Review Your Result: The tool will calculate your BMI and place it into a specific category.
Interpret Your BMI: Based on your BMI, you will receive feedback about your weight status—whether you are underweight, at a healthy weight, overweight, or obese.
Consult a Doctor if Necessary: If your BMI suggests that you are underweight, overweight, or obese, consult a healthcare professional to receive personalized advice.

Example: How the NHS BMI Calculator Works for Adults

Example Calculation:

Age: 40 years old
Height: 175 cm
Weight: 85 kg

After entering this data into the NHS BMI calculator, you might get a result of 27.8, which places the individual in the overweight category. This result suggests that the person may be at a higher risk for certain health conditions and might benefit from lifestyle changes such as diet modifications and exercise.

Tips for Maintaining a Healthy BMI

Healthy Habits to Maintain an Ideal BMI

Regular Exercise: Aim for at least 150 minutes of moderate-intensity exercise each week, including activities like walking, jogging, or swimming.
Healthy Eating: Eat a balanced diet that includes whole grains, lean proteins, fruits, vegetables, and healthy fats. Avoid excessive sugar and processed foods.
Portion Control: Be mindful of portion sizes and practice eating in moderation to prevent overeating.
Reduce Alcohol Intake: Limit alcohol consumption as it can contribute to weight gain and other health issues.
Sleep Well: Getting enough quality sleep (7-9 hours per night) is crucial for maintaining a healthy weight and overall well-being.

Final Words

Monitor Your Weight with the NHS BMI Calculator for Adults

The NHS BMI Calculator for adults provides an easy and accurate way to assess your health. By tracking your BMI, you can gain valuable insights into your weight status, identify potential health risks, and make necessary lifestyle changes. Whether you’re aiming for weight loss or simply maintaining a healthy weight, regular monitoring of your BMI is an essential step towards achieving and maintaining overall health.