More Accurate Than BMI for Fitness Goals
BMI can't tell the difference between fat and muscle — a muscular athlete can be "obese" by BMI. The U.S. Navy method uses your actual body measurements to give a realistic body fat estimate.
US Navy Body Fat Calculator
Calculate your body fat percentage using the official U.S. Navy circumference method. More accurate than BMI — estimates lean body mass and fat category for men and women.
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How to use US Navy Body Fat Calculator
- 1
Select your gender, then enter height and weight (metric or imperial).
- 2
Measure and enter your neck circumference and waist circumference. Women also need hip measurement.
- 3
The calculator applies the U.S. Navy formula and shows your body fat %, lean mass, and which fitness category you fall into.
Why use this tool?
See Your Lean Body Mass
Beyond body fat %, you'll see your fat-free lean mass in pounds or kg. This is your muscle, bone, and organ weight — the number that actually matters for tracking muscle gain or loss.
ACE Fitness Categories: Where Do You Stand?
Compare your result against American Council on Exercise (ACE) body fat ranges — Essential fat, Athlete, Fitness, Acceptable, or Obese — for a clear fitness goal target.
Frequently asked questions
What is the US Navy body fat percentage formula and how does it work?
The U.S. Navy circumference method calculates body fat percentage from circumference measurements (neck, waist, and hips for women) combined with height. Developed by Hodgdon and Beckett in 1984 for naval physical readiness testing, it has a documented accuracy within 3–4% of DEXA scans without needing expensive medical equipment.
How do I measure my waist and neck for the Navy body fat formula?
Neck: measure just below the larynx (Adam's apple) where the neck is narrowest. Waist (men): measure at the navel. Waist (women): measure at the narrowest point. Hips (women only): measure at the widest point around the hips and buttocks. Keep the tape parallel to the floor.
What body fat percentage is considered athletic?
According to ACE guidelines, "athlete" range is 6–13% for men and 14–20% for women. "Fitness" is 14–17% (men) and 21–24% (women). If your goal is a lean athletic look, aim for the lower half of the fitness range.
Why is my result different from what my body fat scale shows?
Smart scales use bioelectrical impedance (BIA), which can be significantly affected by hydration, food intake, and time of day — swinging 3–5% in either direction. The Navy tape method is generally more consistent day to day.
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