BMI Calculator
Calculate your Body Mass Index (BMI) to estimate whether your weight is in a healthy range for your height. This calculator supports both metric and imperial units and shows your BMI category instantly.
How it works
BMI is your weight divided by your height squared. It is a simple screening measure used by health professionals to classify underweight, normal weight, overweight and obesity in adults.
BMI = weight (kg) ÷ height² (m²) — or 703 × weight (lb) ÷ height² (in²)Worked examples
Metric example
A 70 kg adult who is 1.75 m tall: 70 ÷ 1.75² = 70 ÷ 3.0625 = 22.9, which is in the normal-weight range.
Imperial example
A 154 lb adult who is 69 in tall: 703 × 154 ÷ 69² = 22.7, also in the normal-weight range.
Frequently asked questions
What is a healthy BMI?
For most adults, a BMI between 18.5 and 24.9 is considered a healthy weight range.
What are the BMI categories?
Under 18.5 is underweight, 18.5–24.9 normal, 25–29.9 overweight, and 30 or above is obese.
Is BMI accurate for everyone?
BMI does not distinguish muscle from fat, so very muscular people may have a high BMI without excess body fat. It is a screening tool, not a diagnosis.
Is BMI different for children?
Yes. For children and teens, BMI is interpreted against age- and sex-specific percentiles rather than fixed cutoffs.
This tool is for general information only and is not medical advice. Always consult a qualified healthcare professional before making health-related decisions.
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