What is a healthy BMI?

The WHO classifies 18.5–24.9 as the healthy range for most adults, 25–29.9 as overweight, and 30+ as obese.

Is BMI accurate for everyone?

No. BMI does not distinguish muscle from fat, so athletes often score “overweight” while healthy. It is a population screening tool, not a diagnosis.

How is BMI calculated?

Weight in kilograms divided by height in metres squared: kg ÷ m². Imperial inputs are converted to metric first.

Is my health data stored?

No. The calculation runs in your browser and nothing you enter is transmitted or saved.

BMI Calculator

Calculate your Body Mass Index in metric or imperial units and see where it falls on the standard WHO categories. Free and private.

Height (cm) Weight (kg)

— Your BMI

Enter your details

BMI is a screening measure, not medical advice. Consult a healthcare professional about healthy weight for your body.

How to use the BMI Calculator

Choose metric (cm / kg) or imperial (ft+in / lb) units.
Enter your height and weight.
Your BMI and its WHO category appear instantly.

About this tool

Body Mass Index is the standard first-pass screening measure relating weight to height. It takes ten seconds to compute and gives you a rough sense of which weight range you fall into according to World Health Organization categories.

This calculator accepts both metric and imperial units and updates as you type. Because it runs entirely in your browser, your height and weight — health data most people prefer to keep private — never leave your device.

Remember BMI’s limits: it ignores body composition, age, sex and ethnicity. A muscular person can have a “high” BMI at low body fat, and the healthy range can shift for older adults. Treat the number as a conversation starter with a doctor, not a verdict.

Frequently asked questions

What is a healthy BMI?: The WHO classifies 18.5–24.9 as the healthy range for most adults, 25–29.9 as overweight, and 30+ as obese.
Is BMI accurate for everyone?: No. BMI does not distinguish muscle from fat, so athletes often score “overweight” while healthy. It is a population screening tool, not a diagnosis.
How is BMI calculated?: Weight in kilograms divided by height in metres squared: kg ÷ m². Imperial inputs are converted to metric first.
Is my health data stored?: No. The calculation runs in your browser and nothing you enter is transmitted or saved.

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