BMI Calculator
Calculate your Body Mass Index with a visual gauge, healthy weight range, and BMI Prime.
BMI is a quick screening measure, not a diagnosis - it doesn't distinguish muscle from fat, so it can misclassify athletes, and it isn't designed for children, pregnant people, or the elderly. Talk to a healthcare provider for a fuller picture.
Within the typical healthy weight range for your height.
Healthy weight range for your height
56.7 kg - 76.3 kg
Based on a BMI of 18.5-24.9, the WHO-defined "normal weight" range.
Advanced metrics
Ratio of your BMI to the upper healthy limit (25). Under 1.0 is within range.
Like BMI but scales weight by height cubed - less sensitive to height than BMI.
- Underweight<18.5
- Normal weight18.5-25
- Overweight25-30
- Obese (Class I)30-35
- Obese (Class II)35-40
- Obese (Class III)≥40
This calculator provides general estimates for informational purposes only and is not medical advice - consult a qualified healthcare professional before making decisions about your health.
Results are provided "as is" and may contain errors or inaccuracies - please verify them before relying on them, and use this tool at your own risk.
How it works
BMI (Body Mass Index) divides your weight in kilograms by the square of your height in meters (kg/m²). It's a fast screening number used by health organizations worldwide to flag whether someone falls into an underweight, normal, overweight, or obese range at a population level - it doesn't measure body fat directly, so it can be misleading for very muscular people, and isn't designed for children, pregnant people, or the elderly.
Read the full guideHow to use it
- Choose Metric (cm/kg) or Imperial (ft, in/lb) units.
- Enter your height and weight - your BMI, category, and gauge position update instantly.
- Check your healthy weight range and, if you want more detail, expand Advanced metrics for BMI Prime and Ponderal Index.
Examples
Frequently asked
- What BMI ranges count as underweight, normal, overweight, or obese?
- Using the WHO scale: under 18.5 is underweight, 18.5-24.9 is normal weight, 25-29.9 is overweight, and 30+ is obese (split further into Class I, II, and III as it increases).
- Why doesn't BMI account for muscle?
- BMI only uses height and weight - it has no way to tell muscle from fat. A very muscular, lean person can have a "high" BMI despite low body fat, which is BMI's best-known limitation.
- What is BMI Prime?
- BMI Prime is your BMI divided by 25 (the upper bound of the normal range), giving a simple ratio: exactly 1.0 means you're right at the healthy-weight ceiling, under 1.0 means you're within it.
- What's the difference between BMI and the Ponderal Index?
- Both relate weight to height, but the Ponderal Index divides weight by height cubed instead of squared, which makes it less distorted for people who are unusually short or tall.