BMI Calculator
Calculate your Body Mass Index and health category.
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Enter your height and weight to see your BMI result.
About BMI
Body Mass Index (BMI) is a measure of body fat based on height and weight. It helps classify weight categories and assess health risks related to weight.
What Is This Tool?
Our BMI calculator computes your Body Mass Index from your height and weight, and shows where your result falls on the standard BMI scale. BMI is a widely used screening tool to identify potential weight-related health risks. Both metric (kg/cm) and imperial (lb/in) units are supported, and all calculations happen locally in your browser.
How to Use
- Select your preferred unit system: metric or imperial.
- Enter your height in centimeters (or feet and inches).
- Enter your weight in kilograms (or pounds).
- Your BMI result and category appear immediately.
Common Use Cases
- Getting a quick health screening benchmark during a fitness check-in
- Tracking BMI changes over time as part of a diet or exercise plan
- Understanding weight categories for general health awareness
- Converting between metric and imperial measurements for medical forms
Tips & Tricks
- BMI is a screening tool, not a diagnostic measure — consult a doctor for health advice.
- Muscle is denser than fat, so athletes may show a high BMI without being overweight.
- Track your BMI over months, not days — small daily fluctuations are normal.
Frequently Asked Questions
What BMI ranges count as underweight, normal, overweight, or obese?
The standard scale is: under 18.5 underweight, 18.5–24.9 normal weight, 25–29.9 overweight, and 30+ obese. The tool highlights which category your result falls into automatically.
Can I switch between metric and imperial units?
Yes. Toggle the unit system at the top of the calculator to switch between kilograms/centimeters and pounds/feet-inches at any time.
Is BMI accurate for everyone?
BMI doesn't distinguish muscle from fat, so it can overestimate body fat in athletes and underestimate it in people with low muscle mass. It's best used as a general screening indicator, not a precise health diagnosis.
Why does BMI use height squared instead of just height?
Body weight scales roughly with the square of height across a population, so dividing weight by height squared gives a more consistent comparison across people of different heights than dividing by height alone.
Is my height and weight data sent to a server?
No. The BMI calculation runs entirely in your browser — the numbers you enter are never transmitted or stored anywhere.
Calculate your Body Mass Index (BMI) quickly and accurately. Check if your weight is healthy with our free BMI calculator. Get instant results and health insights.
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