BMI Calculator — Calculate Body Mass Index & Healthy Weight
Free online BMI calculator for men, women, and teens. Calculate your exact Body Mass Index, BMI Prime, Ponderal Index, and healthy weight range in metric or imperial units.
How to use this calculator
👉 Fill in the boxes below and your answer appears instantly — no maths needed, we do it all for you! 🎉
In plain English — what does this do?
🏋️ Your body needs food to move, breathe, and grow — just like a car needs petrol. This tool helps you find out how much food your body needs in a day to feel good and stay healthy!
A BMI (Body Mass Index) calculator evaluates your body mass relative to your height to determine if your weight falls within underweight, normal, overweight, or obese ranges according to WHO criteria. It also computes BMI Prime and Ponderal Index for advanced health assessment.
Your BMI Score is 📊
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BMI Prime
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Ponderal Index
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Healthy Weight Range
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| WHO Category | BMI Range |
|---|---|
| Severe Thinness | < 16.0 |
| Moderate Thinness | 16.0 – 16.9 |
| Mild Thinness | 17.0 – 18.4 |
| Normal | 18.5 – 24.9 |
| Overweight | 25.0 – 29.9 |
| Obese Class I | 30.0 – 34.9 |
| Obese Class II | 35.0 – 39.9 |
| Obese Class III | ≥ 40.0 |
What is BMI Calculator — Calculate Body Mass Index & Healthy Weight?
A BMI (Body Mass Index) calculator evaluates your body mass relative to your height to determine if your weight falls within underweight, normal, overweight, or obese ranges according to WHO criteria. It also computes BMI Prime and Ponderal Index for advanced health assessment.
How to use it
- 1️⃣ Select your preferred measurement units: Metric (cm, kg) or Imperial (feet, inches, lbs).
- 2️⃣ Enter your age, biological sex, height, and body weight.
- 3️⃣ Read your exact BMI score, WHO weight category, BMI Prime score, and Ponderal Index.
- 4️⃣ Review your personalized healthy weight target range based on your exact height.
Formula
💡 See it in action — a real example
❓ Common questions
- What is a healthy BMI chart for adult men and women?
- According to the World Health Organization (WHO), a healthy adult BMI ranges from 18.5 to 24.9. A BMI under 18.5 is categorized as underweight, 25.0–29.9 as overweight, and 30.0 or above as obese.
- How do I calculate BMI manually?
- To calculate BMI in metric units, divide your weight in kilograms by your height in meters squared (kg/m²). In imperial units, divide your weight in pounds by height in inches squared, then multiply by 703.
- What is a healthy BMI for adults over 60?
- While WHO standard categories apply to all adults 20 and older, clinical studies suggest a slightly higher BMI range of 23.0 to 27.0 may be protective for adults over 65 against bone loss and illness.
- What is the difference between BMI and Body Fat Percentage?
- BMI measures total weight relative to height but cannot distinguish between muscle and body fat. Body Fat Percentage measures the exact proportion of fat tissue vs lean tissue in your body.
- What is BMI Prime?
- BMI Prime is the ratio of your actual BMI to the upper limit of normal BMI (25.0). A BMI Prime of 1.00 indicates you are exactly at the maximum normal weight threshold. A ratio above 1.00 indicates overweight.