Advanced BMI Calculator
Calculate your BMI with accurate unit conversions
Your Details
Your BMI Results
Ideal Weight Range
Health Risks
Nutrition Tips
BMI Classification Chart
| Category | BMI Range | Health Risk |
|---|---|---|
| Underweight | <18.5 | Moderate |
| Normal | 18.5-24.9 | Low |
| Overweight | 25-29.9 | Moderate |
| Obese | ≥30 | High |
What is BMI and Why It Matters
Body Mass Index (BMI) is a numerical value calculated from your weight and height that provides a reliable indicator of body fatness for most people. Our Advanced BMI Calculator goes beyond basic BMI calculation to give you comprehensive health insights including:
- Accurate BMI score with support for both metric (kg, cm) and imperial (lbs, ft/in) units
- Weight category classification (underweight, normal, overweight, obese)
- Estimated body fat percentage based on your BMI and demographic factors
- Ideal weight range for your height and body type
- Personalized health risks associated with your current BMI
- Nutrition and lifestyle tips tailored to your results
BMI Quick Facts
Healthy BMI Range:
18.5 - 24.9 kg/m²
BMI Formula:
Weight (kg) ÷ [Height (m)]²
Used By:
WHO, doctors, and health professionals worldwide
Limitations:
Doesn't account for muscle mass or body composition
Understanding Your BMI Results
What Does BMI Measure?
Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is BMI = kg/m² where kg is a person's weight in kilograms and m² is their height in meters squared. While BMI doesn't measure body fat directly, research has shown that BMI correlates to direct measures of body fat.
BMI Categories Explained
Underweight (BMI < 18.5)
May indicate malnutrition, eating disorder, or other health problems. Being underweight can weaken your immune system and lead to osteoporosis.
Normal weight (BMI 18.5-24.9)
Associated with lowest health risks. People in this range generally have appropriate weight for their height.
Overweight (BMI 25-29.9)
May indicate excess body weight. Overweight individuals are at higher risk for developing various diseases.
Obese (BMI ≥ 30)
Indicates excessive body fat. Obesity increases risk of serious health conditions like heart disease and diabetes.
BMI Limitations
While BMI is a useful screening tool, it has some limitations:
- May overestimate body fat in athletes and others with muscular builds
- May underestimate body fat in older persons and others who have lost muscle
- Doesn't account for differences in body composition or fat distribution
- May not be equally accurate across all ethnic groups
For a more complete health assessment, consider combining BMI with other measurements like waist circumference and body fat percentage.
How to Improve Your BMI
If your BMI indicates you're outside the healthy range, consider these evidence-based strategies:
For Underweight Individuals
- Consume nutrient-dense foods
- Eat more frequent, smaller meals
- Include strength training to build muscle
For Overweight Individuals
- Reduce portion sizes
- Increase physical activity
- Focus on whole, unprocessed foods