BMI Calculator
حاسبة مؤشر كتلة الجسم BMI
Enter your weight and height to get your BMI, its adult category and the healthy weight range for your height.
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Result
Enter your weight and height.
Body mass index is a simple measure used by doctors and the WHO to estimate whether weight suits height in adults. It's a first screening tool, not a diagnosis.
Enter kilograms and centimetres, or pounds, feet and inches.
Calculation and categories
- Height is converted to metres, then weight is divided by height squared.
- Below 18.5: underweight. 18.5 to under 25: healthy. 25 to under 30: overweight.
- 30 to under 35: obesity class I. 35 to under 40: class II. 40 or more: class III.
- Healthy weight for your height = 18.5 × height² to 24.9 × height².
Formula
BMI = weight (kg) ÷ height (m)²1 lb = 0.45359237 kg; 1 in = 2.54 cm
BMI doesn't separate muscle from fat, so athletes may show as overweight. These categories are not for children and teens (growth charts are used) or pregnancy. See a doctor for a health assessment.
Worked examples
70 kg and 175 cm
70 ÷ (1.75 × 1.75) = 22.9, a healthy weight. The healthy range for this height is about 56.7 to 76.3 kg.
155 lb and 5 ft 9 in
That's 70.3 kg and 175.3 cm, a BMI of about 22.9.
Frequently asked questions
Is BMI accurate?
It's useful at population level but doesn't measure body fat or where it sits. Waist size and body-fat percentage add important context.
Does it work for children?
No. Children and teens are assessed with age- and sex-specific growth charts.
Are cut-offs different for Asian populations?
Some health bodies use lower cut-offs for some Asian populations. We show the general WHO classification.
Content last reviewed: November 1, 2026