BMI

📅 November 15, 2025 ✍️
Free BMI Calculator - Check Your Body Mass Index in Seconds

🧮 Universal BMI Calculator

📋 Personal Details

📏 Measurement Inputs

⚠️ Important Note: BMI categories shown are based on WHO adult standards (Age 20+). For children and teens (2-19 years), different growth charts are used.

📐 BMI Formulas Explained

The Body Mass Index (BMI) measures body fat based on weight and height. The calculation uses the Metric System as the standard.

Metric Formula (Standard)

BMI = Weight (kg) ÷ [Height (m)]²
Example: 70 kg ÷ (1.75 m)² = 22.9

Imperial Formula (Alternative)

BMI = [Weight (lb) ÷ Height (in)²] × 703
Example: [154 lb ÷ (69 in)²] × 703 = 22.7

📊 BMI Categories (Adults 20+)

  • Underweight: BMI less than 18.5
  • Normal Weight: BMI 18.5 - 24.9
  • Overweight: BMI 25.0 - 29.9
  • Obese: BMI 30.0 and above

❓ Frequently Asked Questions

While the same formula calculates BMI for all ages, the interpretation differs significantly. Adult BMI uses fixed cutoff points (18.5, 25, 30). For children and teens (ages 2-19), BMI is compared to growth charts with age- and sex-specific percentiles because body composition changes rapidly during growth.

Though BMI is always calculated metrically (kg/m²), many people in the UK, US, and other regions are more familiar with stones, pounds, feet, and inches. This calculator converts your input automatically, making it easier to use without manual conversions.

No, BMI has limitations. It doesn't distinguish between muscle and fat. Athletes and bodybuilders may have high BMI scores (25-30) that classify them as "overweight," despite having low body fat. For these individuals, body fat percentage, waist-to-hip ratio, or other metrics are more appropriate.

A high BMI can indicate increased health risks, but it's just one indicator. Consult with a healthcare professional who can assess your overall health, including body composition, lifestyle, and medical history. BMI is a screening tool, not a diagnostic tool.

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