What the numbers mean
BMI is your weight in kilograms divided by your height in metres squared. The WHO bands are: below 18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, and 30 or more obese. It's a quick screening figure, not a full health assessment.
Limits of BMI
BMI doesn't tell muscle from fat, so very muscular people can read as "overweight" while the figure can understate body fat in others. It also isn't tuned for children or pregnancy. Treat it as a starting point and talk to a doctor for anything that matters.
Frequently asked questions
What is a healthy BMI?
For most adults a BMI between 18.5 and 24.9 is considered the normal range.
Is BMI accurate for athletes?
Not always — extra muscle adds weight, so athletes can show a high BMI without excess body fat.
Does this store my measurements?
No. The calculation happens in your browser and nothing is saved or uploaded.
Related tools
BMI is a general screening estimate, not a medical diagnosis. Speak to a healthcare professional about your individual health.