1. What is the 3-Site Body Density Equation?

The 3-site skinfold measurement is a method to estimate body density from subcutaneous fat measurements. The equation varies by gender and provides a foundation for calculating body fat percentage.

2. How Does the Calculator Work?

The calculator uses the gender-specific equation:

Where:

• \( BD \) — Body density (g/cm³)
• \( S \) — Sum of three skinfold measurements (mm)
• \( c \) — Gender-specific constant
• \( d \) — Gender-specific constant

Explanation: The equation accounts for the logarithmic relationship between skinfold thickness and body density.

3. Importance of Body Density Measurement

Details: Body density measurement is crucial for estimating body composition, tracking fitness progress, and assessing health risks associated with body fat levels.

4. Using the Calculator

Tips: Enter the sum of three skinfold measurements in millimeters and select gender. Typical measurement sites vary by gender (chest, abdomen, thigh for men; triceps, suprailiac, thigh for women).

5. Frequently Asked Questions (FAQ)

Q1: Which skinfold sites are measured?
A: For men: chest, abdomen, thigh. For women: triceps, suprailiac, thigh.

Q2: How accurate is this method?
A: When performed by a trained professional, it's about ±3.5% accurate for body fat estimation.

Q3: What are normal body density values?
A: Typical ranges are 1.05-1.10 g/cm³ for men and 1.01-1.07 g/cm³ for women, varying by fitness level.

Q4: How should skinfolds be measured?
A: Use calipers at standardized anatomical sites, with the skinfold parallel to its natural cleavage lines.

Q5: Can I convert body density to body fat percentage?
A: Yes, using formulas like Siri or Brozek equations (e.g., %Fat = (495/BD) - 450).