What is BMI?
BMI (Body Mass Index) is a numerical value calculated from your height and weight. It is widely used as a screening tool to identify whether a person is underweight, normal weight, overweight, or obese.
BMI Formula
- Metric: BMI = weight (kg) ÷ height² (m²)
- Imperial: BMI = 703 × weight (lbs) ÷ height² (inches²)
BMI Categories (WHO Standard)
- Below 18.5: Underweight
- 18.5 – 24.9: Normal weight ✅
- 25.0 – 29.9: Overweight
- 30.0 – 34.9: Obese (Class I)
- 35.0 – 39.9: Obese (Class II)
- 40.0 and above: Severely obese (Class III)
How to Calculate Your BMI Online
1Open the BMI Calculator tool.
2Select metric (kg/cm) or imperial (lbs/inches).
3Enter your height and weight.
4See your BMI, category, and healthy weight range instantly.
⚠️ Limitation: BMI does not distinguish between fat and muscle. Athletes with high muscle mass may have a high BMI despite being healthy. Always consult a healthcare professional for a full assessment.
FAQ
Is BMI accurate for everyone?
BMI is a useful screening tool but has limitations. It can overestimate body fat in muscular people (athletes) and underestimate it in older adults who have lost muscle. Children and pregnant women have different BMI interpretations.
What is the ideal BMI for my age?
For adults 18+, a BMI of 18.5–24.9 is considered healthy. For children and teens, healthy BMI ranges vary by age and sex — use age-specific BMI percentile charts instead.