BMI Calculator
Calculate Body Mass Index from height and weight.
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?
- BMI is a screening metric. It does not account for body composition, age or ethnicity.
- Can I use imperial units?
- Choose Imperial, then enter height in feet and inches and weight in pounds.
Formats & limits
- Metric fields show 50–280 cm for height and 10–400 kg for weight
- Outputs BMI, adult WHO categories and a healthy weight range
- Optional waist input adds a waist-to-height guideline
Privacy
Calculations run in your browser. Copy places the summary on your clipboard; Share sends the displayed results through your chosen app.
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Updated
15 October 2025