Advanced Body Fat Calculator
Calculate Body Fat % with Navy, Army, BMI Methods + Lean Mass & FFMI
Published: November 15, 2025 | Updated: November 15, 2025
Published by: RevisionTown Team
Body fat percentage is a key indicator of overall health and fitness, measuring the proportion of fat mass to total body weight. Unlike BMI which only considers height and weight, body fat percentage provides a more accurate picture of body composition by distinguishing between fat mass and lean mass (muscle, bone, organs).
This advanced calculator uses multiple proven methods including the U.S. Navy circumference method, U.S. Army tape test, BMI-based estimation, and calculates additional metrics like lean body mass, fat mass, and FFMI (Fat-Free Mass Index) to provide a comprehensive body composition analysis.
Body Fat Percentage Calculator
Or enter cm:
Or kg:
Body Fat Calculation Formulas
U.S. Navy Method
Most accurate circumference-based method:
Men:
BF% = 495 / (1.0324 - 0.19077 × log₁₀(waist - neck) + 0.15456 × log₁₀(height)) - 450
Women:
BF% = 495 / (1.29579 - 0.35004 × log₁₀(waist + hip - neck) + 0.22100 × log₁₀(height)) - 450
Accuracy: ±3.5% | Measurements in centimeters
U.S. Army Method (2023)
Simplified one-site tape test:
Uses waist circumference at belly button, weight, age, and gender
Proprietary formula adjusted for military standards
Note: 10% more accurate than old multi-site method
BMI Method
Estimate based on BMI, age, and gender:
Adult: BF% = (1.20 × BMI) + (0.23 × Age) - (10.8 × Gender) - 5.4
Gender = 1 for males, 0 for females
Accuracy: Less accurate, best for general population
Additional Calculations
Fat Mass = Weight × (BF% / 100)
Lean Mass = Weight - Fat Mass
FFMI = Lean Mass (kg) / Height² (m²)
Healthy Body Fat Percentage Ranges
Military Standards
U.S. Navy Maximum: Men 22-26% (age-dependent), Women 33-36%
U.S. Army Maximum: Men 20-26% (age-dependent), Women 30-36%
DoD Goal: 18% (men), 26% (women)
Frequently Asked Questions
What is a healthy body fat percentage?
For men: Essential fat 2-5%, Athletes 6-13%, Fitness 14-17%, Average 18-24%, Obese 25%+. For women: Essential fat 10-13%, Athletes 14-20%, Fitness 21-24%, Average 25-31%, Obese 32%+.
How to calculate body fat percentage?
Body fat percentage can be calculated using: 1) U.S. Navy Method (circumference measurements), 2) U.S. Army Method (waist measurement), 3) BMI Method (height/weight), 4) Skinfold calipers, 5) DEXA scan, or 6) Bioelectrical impedance.
What is the U.S. Navy body fat formula?
For men: BF% = 495/(1.0324 - 0.19077×log₁₀(waist-neck) + 0.15456×log₁₀(height)) - 450. For women: BF% = 495/(1.29579 - 0.35004×log₁₀(waist+hip-neck) + 0.22100×log₁₀(height)) - 450. Measurements in centimeters.
How accurate is the Navy body fat calculator?
The U.S. Navy Method has an accuracy of approximately ±3.5% for most people. It's one of the most reliable circumference-based methods and is widely used by military organizations.
What is FFMI and how is it calculated?
FFMI (Fat-Free Mass Index) measures muscularity. Formula: FFMI = (Lean Mass in kg) / (Height in m)². Normal range: 16-20 for men, 14-17 for women. Athletes: 20-22 men, 17-19 women. Natural limit approximately 25 for men.
What's the difference between Army and Navy body fat calculators?
Army Method (2023+) uses single waist measurement at belly button with weight and age. Navy Method uses neck, waist (and hip for women) circumferences with height. Navy method is generally more accurate but requires more measurements.
Track Your Body Composition
Body fat percentage is a more meaningful health metric than weight or BMI alone. This advanced calculator provides multiple validated methods to assess your body composition, including the U.S. Navy circumference method, U.S. Army tape test, and BMI-based estimation. Each method has different accuracy levels and measurement requirements, allowing you to choose based on available tools and desired precision.
Regular monitoring of body fat percentage, lean mass, and FFMI helps track fitness progress, set realistic goals, and make informed decisions about nutrition and training. Whether you're an athlete optimizing performance, military personnel meeting standards, or someone improving overall health, understanding your body composition provides valuable insights beyond what a scale can tell you. Remember that sustainable changes come from consistent habits—use this tool to track progress over time and celebrate improvements in body composition, not just weight.
