BMI Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 27, 2026
Disclaimer: This calculator is provided for informational and educational purposes only and does not constitute financial, medical, legal, or other professional advice. Always consult a qualified professional before making decisions based on these results.
What BMI is used for
Body Mass Index is a simple screening measurement relating weight to height, used by health organizations worldwide as a quick population-level indicator of weight categories.
WHO BMI categories
| BMI Range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 - 24.9 | Normal weight |
| 25.0 - 29.9 | Overweight |
| 30.0 and above | Obese |
Worked example
For a person weighing 70kg at 175cm tall:
BMI = 70 / (1.75)² = 22.9 (Normal weight)
BMI is a screening tool, not a diagnostic measurement - it does not distinguish between muscle and fat mass, so very muscular individuals or older adults with reduced muscle mass can be misclassified. Waist circumference and body composition testing offer additional context beyond BMI alone.