BMI Calculator
Pick Metric or Imperial. Enter your height and weight—your BMI, category, and a healthy weight range will update instantly. Waist is optional for a simple waist-to-height note.
Your BMI
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Healthy weight range
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Waist-to-height note: Enter height and (optionally) your waist to see a quick guideline.
Rule-of-thumb: keep waist less than half your height. A ratio ≥
0.5 may indicate increased health risk; ≥ 0.6 is high.
What is BMI?
BMI estimates body fat from height and weight:
BMI = kg / (m²)
or
BMI = 703 × lb / (in²).
WHO adult categories: <18.5 Underweight · 18.5–24.9 Healthy · 25–29.9 Overweight · 30–34.9 Obesity I · 35–39.9 Obesity II · ≥40 Obesity III.
Note: BMI is a simple screening tool; it doesn’t account for body composition, age, or ethnicity.
Help & FAQ — BMI Calculator
How to use
- Enter your height in centimetres or feet/inches.
- Enter your weight in kilograms or pounds.
- Review the computed BMI and category, adjusting inputs as needed.
Use cases
- Check BMI quickly during a wellness review.
- Track BMI changes alongside fitness goals.
Tips & FAQs
- Is BMI a health diagnosis?
- No—BMI is a screening metric only. Talk to a healthcare professional for medical advice.
- Can I use imperial units?
- Yes—switch units with the toggle and the calculator converts values automatically.
Formats & limits
- Input range: 100–250 cm height, 30–250 kg weight (or equivalent imperial)
- Outputs BMI plus WHO category bands
- For adults only; athletes and children may need specialized charts
Privacy
Calculations run locally in your browser; no data leaves your device.
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Updated
15 October 2025