BMI Calculator
Calculate your body mass index
Kategorie BMI (WHO)
Medical disclaimer
This tool is for educational purposes only and does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your health.
BMI Calculator Online - Calculate Your Body Mass Index
BMI (Body Mass Index) is an international measure used to check whether an adult's weight is healthy for their height. Formula: BMI = weight (kg) ÷ height² (m). Example: 70 kg ÷ (1.75 m)² = 22.9
BMI categories (WHO)
| Category | BMI range |
|---|---|
| Underweight | < 18.5 |
| Normal weight | 18.5 - 24.9 |
| Overweight | 25 - 29.9 |
| Obesity Class I | 30 - 34.9 |
| Obesity Class II | 35 - 39.9 |
| Obesity Class III | ≥ 40 |
How to interpret BMI
BMI relates weight to height in adults. It does not distinguish muscle from fat — an athlete with high muscle mass may have “overweight” BMI while having low body fat. Older adults and pregnancy need careful interpretation; children use age- and sex-specific percentile charts, not adult cut-off values.
Clinical limitations
The calculator output is not a diagnosis or medical advice. If you have chronic conditions, take medications that affect weight, or worry about your weight — consult a clinician or registered dietitian. This text is educational only.
After you calculate BMI
- Waist circumference — complements BMI for metabolic risk (visceral fat).
- Habits — sustainable activity and diet matter more than one number.
- Trends — track over weeks, not day-to-day fluctuations.
- Prevention — follow screening advice from your GP for your age and sex.
FAQ — BMI calculator
Is BMI the same as body fat percentage?
No. BMI is weight/height²; body fat % needs different measurements (e.g. skinfold, DEXA) or formulas.
Why is my BMI “overweight” but I feel healthy?
BMI is a population-level metric. Individual health depends on body composition, fitness and labs — discuss with a doctor.
How often should I check BMI?
Occasionally when height is stable; monthly trends matter more than daily noise.