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BMI Calculator (WHO)Beta

Calculate your BMI from height and weight under the WHO international (US CDC) standard and see your weight category.

Result

Enter your height and weight to see your result.

How to use

Enter your height (cm) and weight (kg) to see your BMI and weight category under the WHO international (US CDC) standard. The bar under the result shows where you fall and the weight at each threshold for your height.

International standard: WHO and CDC (adults 20 and older)

The World Health Organization (WHO) defines overweight as a BMI of 25 or more and obesity as a BMI of 30 or more. The US Centers for Disease Control and Prevention (CDC) uses the same thresholds: under 18.5 is underweight, 18.5 to under 25 is a healthy weight, and obesity is divided into class 1 (30–34.9), class 2 (35–39.9), and class 3 (40 or more, severe obesity). The CDC’s adult categories apply to people aged 20 and older.

Obesity around the world in numbers

According to the WHO, 43% of adults aged 18 and older worldwide — about 2.5 billion people — were overweight in 2022. About 16% of adults, or 890 million people, were living with obesity.

How the CDC describes BMI

The CDC describes BMI as a quick, safe screening measure of weight relative to height. It is not a diagnostic tool: it does not distinguish between fat, muscle, and bone, and it does not show what type of fat a person has or where it is carried in the body. That is why two people with the same BMI can be in very different health.

Limits of BMI

BMI was designed as a quick way to gauge weight status across large populations. People with the same BMI can differ in health depending on muscle mass, fat distribution, age, and sex. Abdominal obesity in particular does not show up in BMI, so it is worth checking your waist circumference as well. Waist thresholds also differ by country, and the Notes section of the result shows the threshold for this standard. Results are for reference only and are not a medical diagnosis.

Sources

Frequently asked questions

At what BMI does obesity start under the US/WHO standard?

A BMI of 25 or more is overweight and 30 or more is obesity. The US CDC divides obesity into class 1 (30–34.9), class 2 (35–39.9), and class 3 (40 or more, severe obesity).

How common is obesity worldwide?

According to the WHO, 43% of adults aged 18 and older worldwide (about 2.5 billion) were overweight in 2022, and about 16% (about 890 million) were living with obesity.

Can BMI alone diagnose obesity?

No. The US CDC describes BMI as a quick screening measure of weight relative to height. BMI cannot distinguish fat, muscle, and bone, and does not show where fat is carried in the body.