The BMI categories in this tool use the adult CDC ranges, underweight below 18.5, healthy weight from 18.5 to below 25, overweight from 25 to below 30, and obesity from 30 or higher. This calculator is for adults, not children or teens.

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BMI Calculator

Use this BMI calculator to estimate your body mass index using your height and weight. BMI is a simple number that compares weight with height.

BMI can be useful as a quick screening tool, but it does not tell the full story about your health. It does not measure body fat directly, and it does not show muscle mass, fitness level, body shape, or medical history.

What is BMI?

BMI stands for Body Mass Index.

It is a calculation based on height and weight. Many people use BMI as a simple way to understand whether their weight is in a general adult range.

BMI is not a diagnosis. It is only a guide.

How this BMI calculator works

This calculator uses your height in centimetres and your weight in kilograms.

It converts your height into metres, then calculates BMI by dividing weight by height squared.

After calculating your BMI, the tool gives a general adult category.

What your BMI result means

Your BMI result gives a simple estimate based on adult BMI ranges.

A BMI below 18.5 is usually classed as underweight.

A BMI from 18.5 to below 25 is usually classed as healthy weight.

A BMI from 25 to below 30 is usually classed as overweight.

A BMI of 30 or higher is usually classed as obesity.

These categories are general. Your personal health can be affected by many other factors.

Why BMI is only a guide

BMI does not measure body fat directly.

A person with more muscle may have a higher BMI without having high body fat. A person with lower muscle mass may have a BMI that looks normal but still have health risks.

This is why BMI should not be used alone to judge health.

BMI for adults

This BMI calculator is designed for adults.

BMI is interpreted differently for children and teenagers because age and growth patterns matter. If you are under 20, use a child or teen BMI tool from a trusted health source.

When BMI may be less useful

BMI may be less useful for athletes, bodybuilders, older adults, pregnant people, and people with certain medical conditions.

In these cases, body composition, waist measurement, health history, and professional advice may give a clearer picture.

How to use your BMI result

Use your BMI result as a starting point.

If your result is outside the healthy adult range, do not panic. One number does not define your health.

Look at your wider lifestyle, including food quality, activity level, sleep, stress, medical history, and how you feel day to day.

Safety disclaimer

This calculator is for general information only. It is not medical advice, nutrition advice, or a replacement for professional guidance.

If you are pregnant, under 20, managing a medical condition, taking medication, recovering from an eating disorder, or unsure about your health, speak with a qualified health professional before making changes.

Frequently asked questions

What does BMI mean?

BMI means Body Mass Index. It is a number based on your height and weight.

Is BMI accurate?

BMI can be useful as a simple screening tool, but it is not perfect. It does not measure body fat directly or show your full health picture.

What is a healthy BMI?

For adults, a BMI from 18.5 to below 25 is usually considered a healthy weight range.

Can BMI be wrong?

Yes. BMI can be misleading for people with high muscle mass, older adults, pregnant people, and people with certain health conditions.

Is BMI the same for men and women?

The calculation is the same, but individual health can still vary based on body composition, age, lifestyle, and medical history.

Should I use BMI to plan weight loss?

BMI can give a general starting point, but it should not be the only number you use. A daily calorie calculator, activity level, body measurements, and professional guidance can give better context.