Calculate your Body Mass Index (BMI) instantly with our advanced calculator. Get personalized insights, health recommendations, and track your progress over time with the best BMI calculator for adults and teens.
Choose metric or imperial to calculate BMI at home with your preferred measurements. Switching units updates the form instantly.
Add accurate height and weight information for the BMI calculator to deliver precise BMI categories for adults and teens.
Tap calculate to see your BMI score, healthy BMI range, and personalized tips for managing BMI for weight loss or gain.
Enter your details to see your BMI results
Body Mass Index (BMI) is a measurement that uses your height and weight to work out if your weight is healthy. BMI is calculated by dividing your weight in kilograms by your height in meters squared (kg/m²). Discover how to calculate BMI at home step-by-step and monitor progress for long-term wellness.
While BMI doesn't directly measure body fat, research shows that BMI is moderately correlated with more direct measures of body fat obtained from skinfold thickness measurements, bioelectrical impedance, densitometry, dual-energy x-ray absorptiometry (DXA), and other methods.
Learn more from the Centers for Disease Control and Prevention BMI guidance.
Review global research on the World Health Organization obesity fact sheet.
Metric: BMI = weight (kg) ÷ height² (m²)
Imperial: BMI = (weight (lbs) ÷ height² (in²)) × 703
Example: If you weigh 70kg and are 1.75m tall, your BMI would be 22.9, placing you in the healthy BMI range for adults.
BMI below 18.5
May indicate malnutrition, eating disorder, or other health problems. Consider consulting a healthcare provider.
BMI 18.5 - 24.9
Indicates optimal weight for health. Maintain this range through balanced diet and regular exercise.
BMI 25.0 - 29.9
Increased risk of health problems. Consider lifestyle changes including diet modification and increased physical activity.
BMI 30.0 and above
Significantly increased risk of serious health conditions. Strongly consider consulting a healthcare professional.
BMI doesn't distinguish between muscle and fat. Athletes and bodybuilders may have high BMI due to muscle mass, not excess fat.
BMI calculations are the same for adults regardless of age or gender, but body composition changes with age and differs between sexes.
Different ethnic groups may have different relationships between BMI and health risks. Some groups may have higher risks at lower BMI values.
While BMI is a useful screening tool, it's important to consult with a healthcare professional for personalized advice. Consider seeking professional guidance if:
Explore the National Heart, Lung, and Blood Institute weight risk factors for more guidance on when to speak with a doctor about BMI results.
BMI is a useful screening tool for most adults, but it has limitations. It may not be accurate for athletes with high muscle mass, pregnant women, elderly individuals, or certain ethnic groups. It's best used alongside other health assessments.
For most people, checking BMI monthly or quarterly is sufficient. If you're actively trying to lose or gain weight, weekly measurements can help track progress. Remember that weight naturally fluctuates daily.
BMI can indicate potential health risks associated with being underweight, overweight, or obese. However, it's just one factor. Other factors like family history, lifestyle, and overall fitness also play important roles in determining health risks.
BMI uses height and weight to estimate body composition, while body fat percentage directly measures the proportion of fat in your body. Body fat percentage is more accurate for assessing health risks, but BMI is easier to calculate and widely used for screening.
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