Health Tools
BMI Calculator
Work out your Body Mass Index in metric or imperial units, and see where it falls against the World Health Organization reference bands. Everything runs in your browser — nothing is sent anywhere.
2Unit systems
5WHO categories
0Data sent to us
∞Free to use
The tool
Calculate your BMI
Enter your weight and height. Switching units converts what you have already typed.
kg
cm
Your BMI
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Reference
What the number means
World Health Organization bands for adults. They do not adjust for age, sex, ethnicity or muscle mass.
< 18.5
Underweight
18.5 – 24.9
Normal weight
25.0 – 29.9
Overweight
30.0 – 34.9
Obesity Class I
35.0 +
Obesity Class II / III
Beyond the number
Habits move the needle more than the metric
BMI is a population screening tool. For an individual, consistent daily habits tell you far more about your health than a single ratio ever will.
30 minutes of moderate exercise daily
Drink around 8 glasses of water per day
Aim for 7–9 hours of quality sleep
Eat whole foods, reduce ultra-processed foods
Take movement breaks if you sit for long hours
Track trends over months, not day-to-day numbers
BMI is a screening tool, not a diagnostic measure. It does not account for muscle mass, bone density, or fat distribution, and it is not validated for children, pregnant people or athletes. Always consult a healthcare professional for medical advice.