⚖️ BMI Calculator

Calculate your Body Mass Index and determine your healthy weight range

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How to Use the BMI Calculator

Body Mass Index (BMI) is a standardized screening metric established by the World Health Organization (WHO) to evaluate weight categories relative to height in adult men and women. It provides an immediate indication of whether an individual is underweight, normal weight, overweight, or obese.

The Mathematical BMI Formulas

Depending on your preferred system of measurement, BMI is calculated using the following equations:

Metric System: BMI = Weight (kg) / [Height (m)]²

Imperial System: BMI = [Weight (lbs) / (Height (in))²] × 703

Step-by-Step Metric Example: For an adult weighing 75 kg with a height of 1.75 meters (175 cm):

  1. Square height: 1.75 × 1.75 = 3.0625 m²
  2. Divide weight: 75 / 3.0625 = 24.49 BMI (Normal weight category)

World Health Organization (WHO) BMI Categories

Category BMI Range (kg/m²) Health Risk Level
Underweight< 18.5Moderate to High
Normal Weight18.5 – 24.9Low / Optimal
Overweight25.0 – 29.9Increased
Obesity Class I30.0 – 34.9High
Obesity Class II35.0 – 39.9Very High
Obesity Class III (Severe)≥ 40.0Extremely High

Limitations of BMI

While BMI is an excellent population-level screening tool, it has notable individual limitations:

Frequently Asked Questions (FAQ)

Q: What is a healthy weight range for my height?
A: A healthy weight range corresponds to a BMI between 18.5 and 24.9. For a height of 175 cm (5'9"), this equals 56.7 kg to 76.3 kg (125 lbs to 168 lbs).

Q: Should men and women use different BMI formulas?
A: The standard BMI mathematical formula is identical for adult men and women. However, women naturally carry a higher percentage of body fat than men at the same BMI score.

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