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.
Runs in your browser
WebAssembly, no server
No signup required
Open and use instantly
Files stay private
Nothing leaves your device
How It Works
Select adult or child BMI calculation
Choose metric (kg/cm) or imperial (lbs/ft) units
Enter your height accurately
Key Features
- 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
About This Tool
Calculate your Body Mass Index (BMI) online for free with our accurate BMI calculator. Determine if you're underweight, normal weight, overweight, or obese based on WHO and CDC guidelines for both adults and children. Perfect for health monitoring, fitness goals, medical consultations, and weight management. Supports both metric (kg/cm) and imperial (lbs/ft) units with instant results and detailed health category explanations. Our browser-based calculator works completely offline for privacy, with no data storage or registration required. Get personalized BMI insights and health recommendations based on your height and weight.
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.
Frequently Asked Questions
For most adults, a healthy BMI is between 18.5 and 24.9 according to WHO standards.
BMI is a general indicator. Athletes and elderly may need additional health assessments.
BMI = weight (kg) / height (m)², or weight (lbs) × 703 / height (inches)².
Yes, includes age-specific BMI percentiles for children and teens.
No, all calculations happen locally in your browser. Your data never leaves your device.
Supports both metric (kilograms/centimeters) and imperial (pounds/feet) units.
Regular monitoring is good, but consult healthcare providers for comprehensive health advice.
BMI estimates body fat but doesn't measure it directly. Other tests may be more accurate.
BMI categorizes your weight status: under 18.5 (underweight), 18.5-24.9 (normal), 25-29.9 (overweight), 30+ (obese).
The same BMI ranges apply to both men and women, though body composition may differ.
BMI is a screening tool, not a diagnostic one. It may not be accurate for athletes, pregnant women, or those with high muscle mass.
BMI of 30 or higher is considered obese according to WHO standards.
Measure height in meters and weight in kg, then divide weight by height squared (kg/m²).
Enter your height and weight in the calculator above to get instant BMI results.
BMI ranges are the same for adults, but children use age-specific percentiles.
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