Body Fat Percentage: What It Means and How to Calculate It

General reference ranges: Men — Essential fat: 2–5%; Athletic: 6–13%; Fitness: 14–17%; Average: 18–24%; Obese: 25%+. Women — Essential fat: 10–13%; Athletic: 14–20%; Fitness: 21–24%; Average: 25–31%; Obese: 32%+.

Essential fat is the minimum needed for organ function, hormone production, and normal physiology. Below this level, serious health consequences follow. Women have higher essential fat requirements due to reproductive biology.

The 'athletic' range corresponds to competitive athletes and people with significant training history. The 'fitness' range represents a healthy, active lifestyle. Most people don't need to be in the athletic range to be healthy — the fitness range is associated with good metabolic health and low disease risk.

The US Navy circumference method estimates body fat using body measurements. For men, measurements needed are neck circumference and waist circumference. For women: neck, waist, and hip circumference. Height is also required.

Formulas: Men: % body fat = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76. Women: % body fat = 163.205 × log10(waist + hips − neck) − 97.684 × log10(height) − 78.387. These formulas were developed and validated by the US Department of Defense.

Measure at the same time of day (morning, pre-workout is ideal), at the same location on the body, and use a non-stretchable tape measure. For the waist, measure at the navel for men and the narrowest point for women. For the neck, measure just below the larynx.

Weight loss and fat loss are not the same. Rapid caloric restriction often causes muscle loss alongside fat loss, worsening your body composition even as your scale weight drops. The goal is to lose fat while preserving — or building — lean mass.

A caloric deficit of 500 calories per day produces roughly 1 pound of fat loss per week (3,500 calories = 1 lb of fat). Combined with progressive resistance training, this deficit can be achieved while preserving or even gaining muscle mass.

Protein intake is critical for body recomposition. Consuming 0.7–1.0 grams of protein per pound of bodyweight while in a caloric deficit supports muscle retention. This is higher than typical dietary guidelines but well-supported by research in people who exercise.