Body Mass Index (BMI) Calculator
Calculate your Body Mass Index quickly and accurately using standard metric or imperial measurements.
Explore standard adult weight categories, understand how the calculation works, and learn what your score indicates.
Enter Your Measurements
Healthy weight
Your BMI is within the standard adult healthy-weight category.
Standard adult range: 18.5 – 24.9
Understanding Your BMI
Body Mass Index (BMI) is a simple numerical calculation comparing weight to height. It is widely used by healthcare professionals as a quick screening tool for adult weight categories.
The BMI Formula
Calculated using weight in kilograms divided by height in meters squared:
Metric Example: 65 kg ÷ (1.70 m × 1.70 m) = 22.5
Standard Adult BMI Categories
| BMI Range | Classification |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy Weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obesity |
Important Considerations
- Muscle vs. Fat: BMI does not distinguish between muscle mass and fat mass.
- Age Factors: Muscle mass naturally decreases as adults age, which BMI does not account for.
- Children & Teenagers: Adult BMI benchmarks do not apply to children or teens (percentiles are used instead).
Frequently Asked Questions
What is considered a healthy BMI for adults?
For most men and women, a healthy BMI ranges between 18.5 and 24.9 based on standard World Health Organization (WHO) and CDC guidelines.
Why is BMI used if it does not measure body fat directly?
BMI provides a quick, non-invasive, and cost-effective screening metric that correlates well with health outcomes across large adult population groups.
How often should I calculate my BMI?
Checking your BMI every few months or during routine health checkups is generally sufficient to track overall long-term weight trends.