BMI Calculator
Calculate your Body Mass Index using the WHO formula. Enter height and weight to...Calculate your Body Mass Index using the WHO formula. Enter height and weight to get your BMI with category classification (Underweight, Normal, Overw...
WHO BMI Categories (Adults 18+)
BMI Formula & Calculation
BMI = weight (kg) ÷ height² (m²)BMI = (weight (lb) × 703) ÷ height² (in²)70 ÷ (1.70)² = 24.2215 ≈ 24.2Recommendation
You're at a healthy weight. Maintain your lifestyle with balanced nutrition.
Disclaimer: BMI is a screening tool, not a diagnostic measure. It doesn't account for muscle mass, bone density, age, or gender. For children and teens, use BMI-for-age percentiles. Always consult a healthcare provider for personalized health advice.
Calculator Features
Why Use BMI Calculator?
WHO Standard Formula
Uses the official World Health Organization BMI formula: weight(kg) ÷ height²(m²) with proper category thresholds.
Visual BMI Spectrum
Color-coded gradient scale shows exactly where your BMI falls from underweight (blue) through normal (green) to obese (red).
Metric & Imperial Units
Switch between kg/cm and lb/ft-in with one click. Both use the same underlying WHO formula for consistent results.
Shows Your Calculation
See the exact math: your weight, height, raw BMI value, and rounded result. Full transparency in how your BMI is computed.
Child Height Warning
Automatically detects heights below 140cm and warns that standard adult BMI categories don't apply to children.
Healthy Weight Range
Calculates your ideal weight range based on your height and BMI 18.5-24.9 (normal category).
When to Use BMI
Health Screening
Quick initial assessment before doctor visits. Know your BMI category beforehand.
Weight Goal Setting
Calculate your target weight for normal BMI range based on your height.
Progress Tracking
Track BMI changes over weeks/months as part of fitness or weight management.
Form Completion
Many health forms, insurance applications, and fitness programs ask for BMI.
How It Works
Choose Metric or Imperial
Select your preferred unit system. Metric uses centimeters and kilograms; Imperial uses feet-inches and pounds.
Enter Height & Weight
Type your measurements. Results calculate instantly as you type - no button to click.
Read Your BMI
See your BMI score (to 1 decimal place), category name, position on the color scale, and healthy weight range.
Review the Calculation
Expand the formula section to see exactly how your BMI was calculated with raw and rounded values.
Important Notes
BMI Has Limits
BMI can't measure body composition. Athletes, elderly, and pregnant women may get misleading results. It's a screening tool, not a diagnosis.
Consistent Measuring
For tracking: weigh yourself same time daily (morning, after bathroom, before food). Use same scale. Weekly averages are more meaningful than daily fluctuations.
Focus on Trends
A single BMI reading is less important than the trend over time. Moving from 28 to 26 over 6 months shows real progress regardless of exact category.