BMI Calculator
Calculate your Body Mass Index (BMI) from weight and height. Check if your weight is in a healthy range.
Health information disclaimer: This calculator provides general informational estimates and is not medical advice. BMI is a screening measure and does not directly measure body fat or overall health. Consult a qualified healthcare professional for personal health advice.
How It Works
BMI is calculated as weight (kg) ÷ height (m)². It's a quick screening tool to determine if your weight is healthy for your height. We also calculate your ideal weight range based on a healthy BMI.
BMI Formula
Metric: BMI = Weight (kg) ÷ Height (m)²
Imperial: BMI = (Weight (lbs) × 703) ÷ Height (in)²
The calculator converts imperial inputs to metric automatically, so both unit systems produce the same BMI value.
Example
For a person who is 175 cm tall and weighs 70 kg, BMI = 70 ÷ (1.75)² = 22.9 (Normal weight).
Limitations of BMI
- Doesn't distinguish muscle from fat: Muscle is denser than fat. Athletes and bodybuilders often register as "overweight" despite being lean and fit.
- Doesn't account for fat distribution: Visceral fat (around the organs) is riskier than subcutaneous fat. BMI can't tell the difference.
- Less accurate for older adults: Older adults lose muscle mass with age, so a "normal" BMI may mask unhealthy body composition.
- Not designed for children or pregnant women: BMI categories apply to adults aged 20+. Children use age-specific percentile charts instead.
BMI is one screening signal, not a complete health picture. For a fuller assessment, combine it with waist circumference, body fat percentage, and blood markers — and consult a healthcare professional.
Frequently Asked Questions
How do I calculate my BMI?
BMI = Weight (kg) ÷ Height (m)². For imperial units: BMI = (Weight (lbs) × 703) ÷ Height (in)². A healthy BMI is typically 18.5-24.9.
What is a healthy BMI?
A healthy BMI is between 18.5 and 24.9. Below 18.5 is underweight, 25-29.9 is overweight, and 30+ is obese. However, BMI doesn't account for muscle mass.
Is BMI accurate?
BMI is a useful screening tool but doesn't distinguish between muscle and fat. Athletes may have high BMI due to muscle. Use BMI alongside other measurements.