BMI Calculator
Calculate your Body Mass Index and understand your healthy weight range
Guide
How it works
BMI (Body Mass Index) is a measure of body fat based on height and weight that applies to adult men and women.
Formula: BMI = weight (kg) / [height (m)]²
BMI Categories:
- Underweight: BMI less than 18.5
- Normal weight: BMI 18.5 to 24.9
- Overweight: BMI 25 to 29.9
- Obese: BMI 30 or greater
What is a healthy BMI?expand_more
A healthy BMI for most adults falls between 18.5 and 24.9. Below 18.5 is considered underweight, 25 to 29.9 is overweight, and 30 or above is classified as obese. These ranges apply to adults aged 20 and over, regardless of sex.
How do I calculate my BMI?expand_more
BMI is your weight in kilograms divided by the square of your height in metres (BMI = kg / m²). In imperial units, multiply your weight in pounds by 703, then divide by your height in inches squared. This calculator does both for you automatically.
Is BMI accurate?expand_more
BMI is a useful, quick screening tool but it has limits. It doesn't distinguish muscle from fat or account for bone density, so it can overestimate body fat in athletes and underestimate it in older adults. Treat it as a starting point, not a diagnosis.
What is a good BMI for my age?expand_more
For adults, the healthy 18.5–24.9 range is not adjusted by age. For children and teens, BMI is interpreted using age- and sex-specific percentile charts instead, so this adult calculator should not be used for anyone under 20.
How can I lower my BMI?expand_more
BMI falls as you reduce body weight through a sustained calorie deficit and regular activity. A gradual loss of about 0.5–1 kg (1–2 lb) per week is widely considered safe. Use our Calorie and BMR calculators to set realistic daily targets.
Next steps