Body Fat Percentage Explained
Executive Summary
Learn the core logic of Body Fat calculator.
Key Takeaways
- Core Formula: Computes body fat using U.S. Navy circumference or Deurenberg BMI methods.
- Precedence: Assess body composition relative to health risks.
- Efficiency: Provides instant analysis.
Formula
U.S. Navy Circumference Method (Male):
BFP = 495 / [1.0324 − 0.19077 · log10(Waist − Neck) + 0.15456 · log10(Height)] − 450
U.S. Navy Circumference Method (Female):
BFP = 495 / [1.29579 − 0.35004 · log10(Waist + Hip − Neck) + 0.22100 · log10(Height)] − 450
Deurenberg BMI Method:
BFP = 1.20 · BMI + 0.23 · Age − 10.8 · (Sex Factor) − 5.4
Body Composition Formulas
Variable Glossary
| Symbol | Meaning & Description |
|---|---|
| BFP | Body Fat Percentage |
| H | Height (cm or inches) |
| W | Waist circumference (cm or inches) |
| N | Neck circumference (cm or inches) |
| Hip | Hip circumference (cm or inches) (females) |
| BMI | Body Mass Index (kg/m²) |
Step-by-Step Worked Example
1. Mapped Variables
Methodology
U.S. Navy Circumference
Gender
MALE
Height
H178 cm
Weight
Wt75 kg
Waist Circumference
W85 cm
Neck Circumference
N38 cm
2. Equation Substitution
Equation with standard inputs
BFP = 495 / [1.0324 − 0.19077 · log10(47.0) + 0.15456 · log10(178.0)] − 450
3. Calculation Steps
Step 1: Calculate Waist-Neck Difference
Waist - Neck = 85.0 - 38.0 = 47.0 cm
Step 2: Evaluate Logarithmic Terms
log10(Waist-Neck) = 1.672098. log10(Height) = 2.250420
Step 3: Solve U.S. Navy Formula
BFP = 495 / (1.0324 - 0.19077 × 1.6721 + 0.15456 × 2.2504) - 450 = 16.44%
Final Resolved Body Fat Percentage16.4%
Body Fat Mass vs. Lean Mass by Weight (Male, Height 175cm)
Fat Mass (kg)
Lean Mass (kg)
Step-by-Step Worked Example
1. Enter gender, age, height, neck, and waist circumferences.
2. The calculator computes Body Fat Percentage using standard equations.
Frequently Asked Questions
Live Simulation
Body Fat Calculator Sandbox
Tweak variables below to see the formula calculate instantly.
30
178
75
Body Fat Percentage
16.4%
ACE Classification
Fitness
Fat Mass
12.3 kg
Lean Mass
62.7 kg
Target Weight (15% BF)
73.7 kg
How This Result Is Calculated (Step-by-Step)
Step 1: Calculate Waist-Neck Difference
Waist - Neck = 85.0 - 38.0 = 47.0 cm
Step 2: Evaluate Logarithmic Terms
log10(Waist-Neck) = 1.672098. log10(Height) = 2.250420
Step 3: Solve U.S. Navy Formula
BFP = 495 / (1.0324 - 0.19077 × 1.6721 + 0.15456 × 2.2504) - 450 = 16.44%
Interactive Tool
Body Fat Calculator
Estimate body fat percentage, fat mass, lean body mass, and target weight using U.S. Navy circumference and BMI methods.