BMI Calculator

Body Mass Index divides your weight by height squared to produce a single number that categorizes you as underweight, normal, overweight, or obese. It has been used by doctors since the 1970s and remains the most common screening tool for weight-related health risks. A BMI of 18.5-24.9 is considered normal, 25-29.9 is overweight, and 30+ is obese. However, BMI has well-known blind spots — it cannot distinguish between muscle and fat, so a muscular athlete may register as overweight despite having low body fat. For most people without significant muscle mass, BMI remains a useful starting point for understanding weight-related health risk.

How to Use This Calculator

1. Enter your height in feet/inches or centimeters
2. Enter your weight in pounds or kilograms
3. View your BMI number and the WHO health classification category
4. Check the healthy weight range for your height to understand your target
5. Consider using this alongside body fat percentage or waist circumference for a more complete picture

Tips & Considerations

• BMI does not account for muscle mass, bone density, or body composition. Bodybuilders routinely have BMIs of 30+ while having 10-15% body fat.
• Waist circumference is actually a better predictor of metabolic disease risk than BMI alone. Men above 40 inches and women above 35 inches face elevated risk regardless of BMI.
• BMI categories were established using data primarily from white European populations. Thresholds may not be equally predictive across all ethnic groups.
• A BMI of 25-27 in adults over 65 is actually associated with the lowest mortality rates — slightly 'overweight' by standard categories may be protective in older adults.