BMI Calculator Online
Use this free online BMI Calculator tool to estimate body mass indexes and health ranges client-side.
How it works & FAQ
Why this is secure?
BMI calculation runs in your browser. Your height and weight are never transmitted to any server.
Step-by-Step Guide
- 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.
Frequently Asked Questions (FAQ)
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.
Height and weight are processed locally in your browser. No data is transmitted.