1. What is the NIH Body Fat Equation?

The NIH (National Institutes of Health) body fat equation estimates body fat percentage from BMI, age, and sex. It provides a simple method to estimate body composition without specialized equipment.

2. How Does the Calculator Work?

The calculator uses the NIH body fat equation:

Where:

• \( BMI \) — Body Mass Index (unitless)
• \( age \) — Age in years
• \( sex \) — 1 for female, 0 for male

Explanation: The equation accounts for the relationship between BMI, age, gender and body fat percentage.

3. Importance of Body Fat Calculation

Details: Body fat percentage is a better indicator of health than weight alone. It helps assess health risks associated with obesity and monitor fitness progress.

4. Using the Calculator

Tips: Enter BMI (calculated as weight(kg)/height(m)²), age in years, and select gender. All values must be valid (BMI > 0, age between 1-120).

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this equation?
A: While useful for population estimates, it may not be precise for individuals, especially athletes or those with unusual body compositions.

Q2: What are healthy body fat percentages?
A: For men: 8-19% (athletes), 20-24% (fitness), 25%+ (obese). For women: 21-33% (athletes), 34-39% (fitness), 40%+ (obese).

Q3: How is BMI calculated?
A: BMI = weight(kg) / height(m)². For imperial units: BMI = (weight(lbs) × 703) / height(in)².

Q4: Are there limitations to this equation?
A: Less accurate for elderly, athletes, pregnant women, and those with extreme body types.

Q5: Should I use this for medical diagnosis?
A: This is for informational purposes only. Consult healthcare professionals for medical advice.