This calculator is for informational purposes only and does not constitute medical advice. Results are estimates based on general formulas. Consult a qualified healthcare professional before making health decisions.
BMI Calculator
Check your Body Mass Index and understand weight health.
Enter your height and weight to see your result.
Body Mass Index is the most widely used screening tool for weight-related health risk. It's also widely misunderstood. BMI is a population-level signal, not a precise individual diagnosis — but for most adults it's a reasonable starting point.
The BMI formula
Metric: BMI = weight (kg) / height (m)². Imperial: BMI = (weight (lbs) × 703) / height (inches)². The result is a unitless number compared against WHO categories: under 18.5 is underweight, 18.5–24.9 is normal weight, 25.0–29.9 is overweight, 30.0+ is obese.
When to use this calculator
Use it as a quick health screening check, especially when paired with waist circumference and a blood pressure reading. Be skeptical of the result if you're an athlete with significant muscle mass — BMI doesn't distinguish muscle from fat, so muscular bodies often score 'overweight' despite low body fat. For older adults (65+), the optimal range tends to skew slightly higher than the standard categories.
Worked example
A 5'10" person weighing 175 lbs: BMI = (175 × 703) / 70² = 25.1. That puts them in the 'overweight' category by exactly 0.1 — a useful illustration of why BMI categories shouldn't be treated as rigid clinical lines.