⚖️ Enter Your Measurements
Enter your height and weight, then click Calculate BMI to see your results.
WHO BMI Classification Table
| BMI Range | Category | Health Risk |
|---|---|---|
| Below 18.5 | Underweight | Nutritional deficiency, low bone density |
| 18.5 – 24.9 | Normal weight | Lowest risk — healthy range |
| 25.0 – 29.9 | Overweight | Mild health risk, monitor lifestyle |
| 30.0 – 34.9 | Obese Class I | Moderate risk — medical review advised |
| 35.0 – 39.9 | Obese Class II | Severe risk — professional guidance needed |
| 40.0 and above | Obese Class III (Morbid) | Very severe risk — urgent medical attention |
How to Use the BMI Calculator
Choose Unit System
Select Metric (kilograms and centimetres) or Imperial (pounds, feet and inches) — whichever you're most comfortable with. The calculator handles both systems accurately.
Enter Your Details
Input your age, height, and weight. Optionally select your gender for reference context. Use your most recent accurate measurements for the best results.
Read Your Results
Instantly see your BMI score, WHO health category, visual gauge, healthy weight range, and personalised health guidance based on your specific measurements.
Why Use ToollLive BMI Calculator?
WHO Standard Formula
Uses the internationally accepted BMI formula: weight (kg) ÷ height (m)². Results align with official WHO classification ranges.
Metric & Imperial
Seamlessly switch between kg/cm and lbs/ft·in. All conversions are handled internally with precision.
Visual BMI Gauge
An animated colour-coded gauge shows exactly where your BMI sits across all health categories at a glance.
Healthy Weight Range
Get your personal healthy weight range (BMI 18.5–24.9) based on your exact height — so you know your target.
Personalised Health Tips
Each category comes with practical, evidence-based health guidance tailored to your specific BMI result.
100% Private
All calculations happen in your browser with JavaScript. No health data is collected, stored, or sent anywhere.
Related Health Tools
View All Health Tools →Free BMI Calculator — Body Mass Index Calculator for Adults
ToollLive's free BMI calculator uses the internationally recognised Body Mass Index formula (weight in kg ÷ height in metres squared) to calculate your BMI instantly. Our tool follows the official WHO BMI classification standards, giving you an accurate health category — Underweight, Normal, Overweight, Obese Class I, II, or III — along with your personal healthy weight range and evidence-based health guidance.
Whether you prefer metric (kg and cm) or imperial (lbs, feet and inches), our calculator handles both. Enter your age, height, and weight to get your BMI score displayed on a colour-coded gauge that shows exactly where you fall across all categories. You also get your ideal weight range based on your height, and how much weight you would need to lose or gain to enter the healthy zone. No sign-up required, no data stored — completely private and free.
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