BMI Calculator
Your BMI
Normal weight22.9kg/m²
- Healthy weight range
- 56.7 – 76.6 kg
- BMI prime
- 0.91
Show how it’s worked outHide working
70 ÷ (1.75 × 1.75) = 22.9. BMI is a screening number, not a diagnosis — it doesn't account for muscle mass.
About BMI
Body mass index divides your weight in kilograms by the square of your height in metres. The World Health Organization groups adult results into four bands: underweight (below 18.5), normal (18.5–24.9), overweight (25–29.9) and obese (30 and above).
Formula: BMI = weight (kg) ÷ height (m)². In imperial units, BMI = weight (lb) ÷ height (in)² × 703. BMI prime is your BMI divided by 25, so anything under 1.0 sits inside the normal range.
Because it only uses height and weight, BMI can misread athletes, older adults and people with a lot of muscle. Treat it as a starting point and talk to a clinician for anything that concerns you.
Common questions
- What is a healthy BMI?
- For adults, the World Health Organization classes a BMI of 18.5 to 24.9 as the normal range. Below 18.5 is underweight, 25 to 29.9 is overweight and 30 or above is obese.
- How is BMI calculated?
- BMI is your weight in kilograms divided by your height in metres squared. In imperial units it is weight in pounds divided by height in inches squared, multiplied by 703.
- Is BMI accurate for everyone?
- No. BMI does not distinguish muscle from fat, so athletes can read as overweight and older adults can read as normal while carrying excess fat. It is a screening number, not a diagnosis.
Categories
- Underweight< 18.5
- Normal18.5 – 24.9(your result)
- Overweight25 – 29.9
- Obese≥ 30