BMI Calculator

Calculate Body Mass Index and see your healthy weight range.

cm
kg
Your BMI
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Healthy weight range
Healthy BMI
18.5 – 24.9

BMI is a general screening tool, not a diagnosis. It does not account for muscle mass, body composition, age or pregnancy. Speak to a healthcare professional about your individual health.

What BMI measures

Body Mass Index compares your weight to your height to give a single number used as a rough screening category for population health. It is calculated as weight in kilograms divided by height in metres squared.

BMI = weight (kg) ÷ height (m)²

Under 18.5Underweight
18.5 – 24.9Healthy weight
25 – 29.9Overweight
30 and overObese

Because BMI ignores how much of your weight is muscle versus fat, athletes and very muscular people may read as “overweight” while being perfectly healthy. Treat it as a starting point for a conversation with a professional, not a verdict.

Worked example

Someone 1.75 m tall weighing 70 kg has a BMI of 70 divided by 1.75 squared, which is about 22.9 — within the healthy range of 18.5 to 24.9. For that height, a healthy weight is roughly 57 to 76 kg.

Why a healthy weight range matters

Across large populations, sitting within a healthy weight range is associated with a lower risk of conditions such as type 2 diabetes, high blood pressure and heart disease, and it can mean easier movement, better sleep and more day-to-day energy. These are general patterns, though — they describe groups of people, not any single individual.

BMI is a starting point, not the whole story

BMI uses only height and weight, so it cannot see how much of your weight is muscle, where fat sits on your body, or differences related to age, sex and ethnicity. A very fit, muscular person can read as "overweight" while being entirely healthy, and two people with an identical BMI can be in very different health.

A balanced way to use it

Treat your result as one signal among many — alongside things like waist measurement, activity, sleep and how you actually feel. Sustainable habits and overall wellbeing matter far more than any single number, and a doctor or other qualified professional can give guidance that fits your own circumstances.

Frequently asked questions

Is BMI accurate for everyone?
No. BMI does not distinguish muscle from fat, so very muscular people can read high while being lean. It is also less reliable for older adults, children and during pregnancy.
What counts as a healthy BMI?
For most adults, 18.5 to 24.9 is considered the healthy range. It is a screening category rather than a diagnosis of health.
Is there a better measure than BMI?
Waist circumference and waist-to-height ratio capture fat distribution that BMI misses, and a clinician can assess body composition more directly.
Does BMI differ for men and women?
The standard adult categories are the same for men and women, though average body composition differs. Children and teenagers are assessed with age- and sex-specific percentiles instead.