BMI Calculator Online
Estimate body mass indexes and health ranges.
How to use BMI Calculator
- 1Select your unit system: metric (kg/cm) or imperial (lbs/inches).
- 2Enter your height and weight.
- 3Your BMI is calculated instantly along with your weight category and the healthy weight range for your height.
Privacy & security
BMI calculation runs in your browser. Your height and weight are never transmitted to any server.
Height and weight are processed locally in your browser. No data is transmitted.
Frequently asked questions
What do the BMI categories mean?
Underweight: BMI < 18.5. Normal weight: 18.5-24.9. Overweight: 25-29.9. Obese: BMI ≥ 30. These are the WHO's standard ranges for adults.
Is BMI an accurate health measure?
BMI is a screening tool, not a diagnostic one. It doesn't account for muscle mass, bone density, or fat distribution. Athletes may have a high BMI despite low body fat.
Can I calculate BMI for children?
Standard BMI categories apply only to adults (20+). For children, BMI-for-age percentiles are used — consult a pediatric BMI chart.
What is a healthy BMI?
18.5-24.9 for adults using WHO guidelines. Optimal ranges vary by ethnicity — Asian populations typically use 17.5-22.9 as the normal range.