BMI calculator
Enter your height and weight in metric or imperial units to get your body mass index and the healthy weight range for your height.
Your BMI
For adults 18 and over. A screening estimate, not medical advice.
How it works
BMI = weight (kg) ÷ height (m)²BMI = 703 × weight (lb) ÷ height (in)²The healthy range for a height is the weight that gives a BMI from 18.5 to 24.9.
Worked example
175 cm and 72 kg:
- 1.75² = 3.0625
- 72 ÷ 3.0625 = 23.5
- BMI 23.5: normal weight
Frequently asked questions
What is a healthy BMI?
For adults the World Health Organization uses: under 18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, 30 and above obesity.
Is BMI accurate for everyone?
No. It does not tell muscle from fat, so very muscular people can show as overweight, and it is less reliable for older adults. Children and teenagers need age- and sex-specific charts. It is a screening number, not a diagnosis.
Does this give medical advice?
No. For decisions about your health, talk to a doctor.