BMI Calculator
Calculate Body Mass Index for adults using Metric or Imperial units with WHO weight classifications.
⚙️ Body Measurements
📊 BMI Classification
Your Body Mass Index
22.9
Normal Weight (Healthy)
| WHO Category | BMI Range |
|---|---|
| Underweight | < 18.5 |
| Normal Weight | 18.5 – 24.9 |
| Overweight | 25.0 – 29.9 |
| Obesity | ≥ 30.0 |
How to Use This Calculator
- Step 1: Select metric or imperial units.
- Step 2: Enter your height and weight to view your BMI score and WHO classification.
Formula & Calculation Method
Metric: BMI = kg / m² | Imperial: BMI = (lbs / inches²) × 703
Where the variables represent:
| Variable | Description & Units |
|---|---|
| kg / lbs | Body weight |
| m / inches | Standing height |
Worked Calculation Example
Scenario:
Adult height 175 cm (1.75 m) and weight 70 kg.
- Height squared = 1.75² = 3.0625
- BMI = 70 / 3.0625 = 22.85
Result: BMI is 22.9, falling in the Normal Weight category.
Frequently Asked Questions
What are the WHO BMI ranges?
Underweight is under 18.5, normal weight is 18.5-24.9, overweight is 25-29.9, and obesity is 30 or higher.
Related Health & Fitness Tools
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→ BMR & Calorie Calculator
Estimate daily resting metabolic rate (Mifflin-St Jeor) and total maintenance calories.
Accuracy & General Guidance Disclaimer: This calculation tool is provided for educational and practical planning purposes. Formulas are verified against standard mathematical models. Do not rely on estimates as certified professional, financial, legal, or medical advice.