BMI Calculator
Calculate your Body Mass Index using U.S. or metric units and see your weight category.
Your BMI
Enter your height and weight
BMI is a screening tool, not a diagnosis. It doesn't account for muscle mass, bone density,
or body composition — talk to a doctor for a full health assessment.
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How BMI is calculated
Body Mass Index (BMI) uses your height and weight to estimate whether you're in a healthy weight range. In U.S. units: BMI = weight (lb) ÷ height (in)² × 703. In metric units: BMI = weight (kg) ÷ height (m)².
BMI categories (CDC standard)
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obesity |
Source: U.S. Centers for Disease Control and Prevention (CDC) adult BMI categories.
Frequently asked questions
- Is BMI accurate for everyone?
- BMI doesn't distinguish muscle from fat, so it can overestimate body fat in athletes and underestimate it in older adults with low muscle mass.
- What's a healthy BMI?
- For most adults, the CDC considers 18.5–24.9 a healthy weight range, but individual health depends on many other factors too.