Calculators
BMI Calculator
Calculate your Body Mass Index (BMI) instantly with our free BMI calculator. Support for metric (kg, cm) and imperial (lbs, ft, in) units. Get your BMI classification and healthy weight range.
Use BMI Calculator to get instant results without uploads or sign-ups. Everything runs securely in your browser for fast, reliable output.
Your results will appear here.
About this tool
Calculate your Body Mass Index (BMI) quickly and accurately with our free BMI calculator. Enter your height and weight to instantly determine your BMI, see your weight category classification, and discover your healthy weight range. Our calculator supports both metric (kilograms, centimeters) and imperial (pounds, feet, inches) units for worldwide accessibility.
BMI is a simple screening tool used by healthcare professionals worldwide to assess if a person's weight is healthy for their height. While BMI doesn't directly measure body fat, it provides a useful indicator of weight status and potential health risks. Our calculator follows the same BMI formula used by the CDC, WHO, and medical professionals.
Understanding your BMI helps you make informed decisions about your health and fitness goals. The calculator instantly shows your BMI number, classification (underweight, normal weight, overweight, or obese), and the healthy weight range for your height. This information can be valuable when discussing health goals with your doctor or planning lifestyle changes.
Our BMI calculator works on all devices with complete privacy - your health data never leaves your browser. Unlike other calculators loaded with ads and requiring registration, ours is fast, free, and respects your privacy. Bookmark this page to check your BMI anytime, even offline.
Usage examples
Adult Male - Metric Units
Height: 180 cm, Weight: 75 kg
BMI = 23.1 (Normal weight). Healthy weight range for 180 cm: 60-81 kg. Formula: 75 ÷ (1.8)² = 23.1
Adult Female - Imperial Units
Height: 5'4" (64 inches), Weight: 140 lbs
BMI = 24.0 (Normal weight). Healthy weight range for 5'4": 108-145 lbs. Formula: (140 ÷ 64²) × 703 = 24.0
Tracking Weight Loss Progress
Initial: 95 kg at 175 cm (BMI 31.0 - Obese), Current: 80 kg
New BMI = 26.1 (Overweight). Progress: Lost 15 kg, reduced BMI by 4.9 points. Target for normal weight: 77 kg (BMI 25.0)
Fitness Goal Setting
Height: 6'0" (183 cm), Current: 220 lbs (100 kg), BMI: 29.8
Current: Overweight. Healthy range: 137-183 lbs (62-83 kg). To reach normal weight (BMI 24.9): Need to lose approximately 37 lbs
Health Check Assessment
Height: 170 cm, Weight: 52 kg
BMI = 18.0 (Underweight). Healthy weight range: 53-72 kg. Recommendation: Consult healthcare provider for healthy weight gain strategies
How to use
- Optional: Select a Quick Start preset for common profiles (Average Adult Male, Female, Athlete, etc.)
- Choose your preferred unit system (metric: kg/cm or imperial: lbs/inches)
- Enter your weight (in kg or lbs depending on your selection)
- Enter your height (in cm or inches depending on your selection)
- Click "Run Tool" to calculate your BMI instantly and get comprehensive results
- View your BMI value, weight category (Underweight/Normal/Overweight/Obese), and health classification
- See your healthy weight range, ideal BMI target, and weight adjustment recommendations
- Review health risks associated with your BMI category and personalized recommendations
- Compare your BMI against all WHO categories with visual positioning
- Each output has a Copy button for easy sharing or record-keeping
Benefits
- Supports both metric and imperial units - use kg/cm or lbs/ft/in
- Instant BMI calculation with clear classification (underweight/normal/overweight/obese)
- Shows healthy weight range specific to your height
- Uses WHO and CDC standard BMI formulas for accuracy
- No registration or personal information required
- Complete privacy - calculations done in your browser only
- Mobile-friendly design works on phones, tablets, and desktops
- Free forever with no ads or distractions
- Educational - explains what BMI means and its limitations
- Bookmark and use offline anytime
FAQs
What is BMI and how is it calculated?
BMI (Body Mass Index) is your weight in kilograms divided by your height in meters squared (kg/m²). For imperial units, the formula is: (weight in pounds × 703) ÷ (height in inches)². It's a screening tool that indicates whether your weight is healthy for your height. WHO defines healthy BMI as 18.5-24.9 for adults.
What is a healthy BMI range?
According to the WHO and CDC, a healthy BMI for adults is 18.5-24.9. Below 18.5 is underweight, 25-29.9 is overweight, and 30+ is obese. These ranges are guidelines for adults aged 20+ and may not apply to athletes, pregnant women, or people under 20.
Is BMI accurate for everyone?
BMI is a useful screening tool but has limitations. It doesn't distinguish between muscle and fat, so muscular athletes may have high BMI despite low body fat. Bodybuilders and athletes often have "overweight" BMI due to muscle mass. It also doesn't account for age, sex, bone density, or fat distribution. Use BMI as one indicator of health, not the only measure.
Can I use this BMI calculator if I use imperial units?
Yes! Our calculator supports both metric (kg, cm) and imperial (lbs, inches) units. Simply select your preferred unit system from the dropdown and enter your measurements. The calculator automatically uses the correct formula for your selected units and provides results in your chosen system.
What should I do if my BMI is outside the healthy range?
If your BMI indicates underweight or overweight status, consult with your healthcare provider. They can assess your overall health, consider other factors like muscle mass and body composition, and provide personalized advice for reaching a healthy weight safely. Don't use BMI alone to make health decisions.
How often should I check my BMI?
For weight management, checking BMI monthly or quarterly is sufficient to track progress. For general health monitoring, checking once or twice a year is adequate. Focus on long-term trends rather than daily fluctuations, as weight can vary day to day due to hydration, food intake, and other factors.
Is BMI different for men and women?
The BMI formula is the same for both men and women. However, at the same BMI, women typically have more body fat than men due to biological differences. Despite this, the same BMI categories (underweight, normal, overweight, obese) apply to both sexes for screening purposes according to WHO standards.
Does this calculator work for children and teenagers?
This calculator is designed for adults 20 years and older. For children and teens (2-19 years), BMI is calculated the same way but interpreted differently using age and sex-specific percentile charts (BMI-for-age). Consult your pediatrician for children's BMI assessment as they use different standards.
Does BMI account for muscle mass?
No, BMI does not distinguish between muscle and fat tissue. This is a major limitation. Athletes, bodybuilders, and very muscular individuals often have "overweight" or "obese" BMI classifications despite having low body fat percentages. Muscle is denser than fat, so someone with high muscle mass will have a higher BMI. For athletes, body composition analysis or waist circumference measurements are better indicators than BMI alone.
Are BMI standards different for Asian populations?
Yes, some health organizations use modified BMI cutoffs for Asian populations. The WHO Western Pacific Region suggests lower thresholds: overweight at 23-24.9, obese at ≥25, and increased health risk at ≥23. This is because research shows Asian populations have higher body fat percentages and increased health risks at lower BMIs compared to Western populations. However, our calculator uses the standard WHO international classification (18.5-24.9 healthy range) as it's most widely recognized globally.
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