BMI Calculator
Calculate your Body Mass Index to assess your weight relative to your height.
About Body Mass Index (BMI)
Body Mass Index (BMI) is a widely used screening tool that helps assess whether a person has a healthy body weight for their height. It's calculated by dividing your weight in kilograms by the square of your height in meters (kg/m²).
While BMI is useful for identifying potential weight problems in adults, it's important to remember that it's not a diagnostic tool. BMI doesn't directly measure body fat or account for factors like muscle mass, bone density, gender, or age.
BMI Formula
Metric Units
BMI = weight(kg) / height(m)²
Example: A person weighing 70 kg and 1.75 m tall has a BMI of 22.9.
Imperial Units
BMI = 703 × weight(lb) / height(in)²
Example: A person weighing 154 lbs and 5'9" (69 inches) tall has a BMI of 22.7.
BMI Categories and Health Implications
| BMI Range | Category | Health Implications |
|---|---|---|
| Below 18.5 | Underweight | Potential malnutrition, weakened immune system, vitamin deficiencies. |
| 18.5 - 24.9 | Normal weight | Lower risk of heart disease, stroke, and type 2 diabetes. |
| 25 - 29.9 | Overweight | Increased risk of heart disease, stroke, and type 2 diabetes. |
| 30 - 34.9 | Obesity (Class 1) | High risk of heart disease, stroke, type 2 diabetes, and certain cancers. |
| 35 - 39.9 | Obesity (Class 2) | Very high risk of obesity-related health problems. |
| 40 or higher | Severe Obesity (Class 3) | Extremely high risk of serious health conditions. Medical intervention often necessary. |
Limitations of BMI
- Doesn't distinguish between fat and muscle: Athletes and bodybuilders may have high BMIs due to muscle mass, not excess fat.
- Doesn't account for body composition: Two people with the same BMI may have very different body fat percentages.
- Doesn't consider age: Older adults often have more body fat than younger adults with the same BMI.
- Not suitable for children: For children and teens, age and gender-specific BMI percentiles are used instead.
- May not be accurate for certain ethnicities: Research suggests different BMI thresholds may be more appropriate for some ethnic groups.
Tips for Maintaining a Healthy Weight
- Balanced diet: Focus on whole foods, plenty of fruits and vegetables, lean proteins, and whole grains.
- Regular physical activity: Aim for at least 150 minutes of moderate aerobic activity or 75 minutes of vigorous activity per week.
- Strength training: Include muscle-strengthening activities at least twice per week.
- Adequate hydration: Drink plenty of water throughout the day.
- Mindful eating: Pay attention to hunger cues and avoid emotional or distracted eating.
- Sufficient sleep: Aim for 7-9 hours of quality sleep per night.
- Regular health check-ups: Monitor your health with regular visits to healthcare providers.