BMI Calculator
Check your Body Mass Index (BMI) and weight category online using Metric or Imperial units with our BMI Calculator. Instantly assess your health based on official WHO guidelines—fast, accurate, and private.
About This Tool
Learn what makes this tool special
What is BMI? Body Mass Index (BMI) is a numerical value derived from a person's height and weight. It provides an estimate of body fat and helps categorize individuals as underweight, normal weight, overweight, or obese. Developed by Adolphe Quetelet in the 19th century, BMI serves as a screening tool for potential weight-related health issues.
How BMI is Calculated: The BMI formula is BMI = weight (kg) ÷ height (m)². For imperial units: BMI = [weight (lbs) × 703] ÷ height (inches)². Example: A 70kg person who is 1.75m tall has BMI = 70 ÷ (1.75 × 1.75) = 22.86.
BMI Categories (WHO Standards): Underweight (BMI < 18.5), Normal weight (18.5-24.9), Overweight (25-29.9), Obese Class I (30-34.9), Obese Class II (35-39.9), Obese Class III (≥ 40).
Limitations of BMI: BMI doesn't distinguish between muscle and fat, doesn't account for age/gender differences, and may not be accurate for athletes, pregnant women, or the elderly. Additional measurements like body fat percentage or waist circumference provide better health insights.
Key Features
What makes this tool special
- Calculate BMI for adults and children
- WHO and CDC standard health categories
- Metric and Imperial unit support
- Age-specific BMI percentiles for children
- Instant BMI calculation with health assessment
- Visual BMI category indicators
- Health risk explanations and recommendations
- No registration or data storage required
- Works offline in your browser
- Mobile-friendly responsive design
- BMI history tracking and comparison
- Export BMI results and reports
- Educational BMI information and tips
- Secure local processing with complete privacy
- Multiple language and unit preferences
- BMI calculator with detailed explanations
Quick Guide
Master this tool in seconds
- 1Select adult or child BMI calculation
- 2Choose metric (kg/cm) or imperial (lbs/ft) units
- 3Enter your height accurately
- 4Enter your weight
- 5For children, enter age for percentile calculation
- 6Click 'Calculate BMI' for instant results
- 7Review your BMI category and health insights
Common Questions
Everything you need to know
Q.What is a healthy BMI range?
For most adults, a healthy BMI is between 18.5 and 24.9 according to WHO standards.
Q.Is BMI accurate for everyone?
BMI is a general indicator. Athletes and elderly may need additional health assessments.
Q.How is BMI calculated?
BMI = weight (kg) / height (m)², or weight (lbs) × 703 / height (inches)².
Q.Can children use this calculator?
Yes, includes age-specific BMI percentiles for children and teens.
Q.Is my health data stored?
No, all calculations happen locally in your browser. Your data never leaves your device.
Q.What units can I use?
Supports both metric (kilograms/centimeters) and imperial (pounds/feet) units.
Q.How often should I check my BMI?
Regular monitoring is good, but consult healthcare providers for comprehensive health advice.
Q.Does BMI measure body fat?
BMI estimates body fat but doesn't measure it directly. Other tests may be more accurate.
Q.What does my BMI mean?
BMI categorizes your weight status: under 18.5 (underweight), 18.5-24.9 (normal), 25-29.9 (overweight), 30+ (obese).
Q.Is BMI different for men and women?
The same BMI ranges apply to both men and women, though body composition may differ.
Q.Can BMI be wrong?
BMI is a screening tool, not a diagnostic one. It may not be accurate for athletes, pregnant women, or those with high muscle mass.
Q.What BMI is considered obese?
BMI of 30 or higher is considered obese according to WHO standards.
Q.How to calculate BMI manually?
Measure height in meters and weight in kg, then divide weight by height squared (kg/m²).
Q.BMI calculator for height and weight
Enter your height and weight in the calculator above to get instant BMI results.
Q.BMI ranges by age
BMI ranges are the same for adults, but children use age-specific percentiles.
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