BMI Calculator

Calculate your Body Mass Index using metric or imperial units. Get your classification and healthy weight range instantly.

About BMI Calculator

This free BMI calculator uses the standard WHO classification to determine your body mass index. Support for both metric (cm/kg) and imperial (ft/in/lbs) units makes it accessible anywhere. Along with your BMI score and category, you will see a healthy weight range for your height and a color-coded scale that visualizes where you fall on the BMI spectrum.

Metric & Imperial

Switch seamlessly between centimeters/kilograms and feet/inches/pounds with a single click.

WHO Classification

Your BMI is classified according to the World Health Organization standard — underweight, normal, overweight, or obese.

Healthy Weight Range

See the ideal weight range for your height to help set realistic health and fitness goals.

No Registration

Your health data stays on your device. No accounts, no tracking, no data stored.

📋 Common Use Cases

Track Your Health Progress

Monitor changes in your health metrics over weeks and months. Regular tracking helps you see trends, stay motivated, and adjust your fitness or nutrition plan based on real data.

Set Realistic Fitness Goals

Use your calculated metrics to set achievable weight, nutrition, and fitness targets. Understand your baseline numbers before starting any new diet or exercise program.

Professional Health Assessment

Healthcare professionals, personal trainers, and coaches can quickly compute client metrics during consultations without accessing specialized equipment or software.

Nutrition & Diet Planning

Use your results to plan meal portions, macronutrient targets, and daily calorie budgets. Combine multiple health calculators for a complete wellness picture.

🪜 How to Use This Tool

  1. Enter your body measurements
    Fill in the required fields — typically height, weight, age, and gender. Use the unit toggles if you prefer metric or imperial units.
  2. Add optional details if available
    Some calculators accept additional inputs like activity level, waist circumference, or body fat percentage for more precise results.
  3. Review your calculated metrics
    Your results appear instantly with clear labels and reference ranges. Color-coded indicators show where you fall on standard health classification scales.
  4. Track changes over time
    Bookmark the page and return periodically to recalculate. Comparing results over weeks and months reveals meaningful health trends.

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Frequently Asked Questions

Are these calculators really free?▼
Yes. All calculators on iluv.tools are completely free. No signup, no account, no credit card required. Every calculation runs instantly in your browser.
Is my data sent anywhere?▼
Absolutely not. All calculators are pure client-side JavaScript. Your numbers, dates, and inputs never leave your browser. No server processing, no tracking.
How accurate are these calculators?▼
Calculators use standard mathematical formulas with double-precision floating point. Results match industry-standard financial and scientific calculations.
Can I use calculators on mobile?▼
Yes. All calculators work on mobile browsers (iOS Safari, Android Chrome) with responsive layouts.