BMI Calculator
Calculate your Body Mass Index (BMI) to understand your weight category and get personalized health insights. BMI is a widely-used screening tool recommended by the World Health Organization (WHO).
BMI Categories (WHO Classification)
The World Health Organization (WHO) classifies BMI into the following categories for adults:
| BMI Range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 – 34.9 | Obesity Class I |
| 35.0 – 39.9 | Obesity Class II |
| 40.0 and above | Obesity Class III |
Source: World Health Organization (WHO). Note: For Asian populations, lower BMI cut-offs may apply (overweight: 23+, obese: 25+).
How BMI is Calculated
BMI is calculated using a simple formula:
For example, a person weighing 70 kg with a height of 1.75 m would have a BMI of:
Limitations of BMI
- -Does not distinguish between muscle mass and fat mass
- -May overestimate body fat in athletes and muscular individuals
- -May underestimate body fat in elderly or sedentary individuals
- -Does not account for body fat distribution (waist-to-hip ratio is also important)
- -Not suitable for children, pregnant women, or highly muscular individuals
Frequently Asked Questions
What is BMI?
Body Mass Index (BMI) is a simple measure using your height and weight to estimate body fat. It is calculated by dividing your weight in kilograms by the square of your height in meters (kg/m²). It is widely used as a screening tool for weight categories.
Is BMI accurate for everyone?
BMI is a useful screening tool but has limitations. It may overestimate body fat in athletes and muscular individuals, and underestimate it in older persons or those who have lost muscle mass. It does not distinguish between fat, muscle, and bone mass.
What is a healthy BMI range?
A BMI between 18.5 and 24.9 is generally considered healthy for most adults. However, optimal BMI can vary based on age, sex, ethnicity, and muscle mass. For Asians, WHO recommends using lower cut-off points (23 for overweight, 25 for obese).
How often should I check my BMI?
It is recommended to check your BMI at least once a year during your annual health checkup. If you are actively trying to lose or gain weight, monthly tracking can help monitor progress.
Can children use this BMI calculator?
This calculator is designed for adults (18+ years). For children and teens, BMI is calculated differently using age and sex-specific percentiles. Consult a paediatrician for child BMI assessment.
What should I do if my BMI is too high or too low?
If your BMI is outside the normal range, consult a healthcare professional. They can assess your overall health, consider factors BMI doesn't measure, and create a personalized plan. You can book an appointment with a doctor on Zospital for expert guidance.
Medical Disclaimer
The content provided on Zospital is for general informational and educational purposes only. It is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. If you think you may have a medical emergency, call your doctor or emergency services immediately.