How accurate is the US Navy Method?

The US Navy Method has a standard error of approximately ±3–4% body fat when compared to DEXA scans. It is most accurate for people within a normal weight range. It tends to underestimate body fat in obese individuals and can overestimate in very lean or muscular people. For research-grade accuracy, hydrostatic weighing or DEXA scanning is required.

What is the difference between body fat % and BMI?

BMI uses only height and weight — it cannot distinguish fat from muscle. Body fat percentage directly estimates how much of your weight is fat tissue. Two people can have the same BMI but very different body fat percentages. A 80kg person who is mostly muscle has a healthy body fat percentage despite a potentially "overweight" BMI.

What is visceral fat and why does it matter?

Visceral fat is fat stored around internal organs in the abdominal cavity — distinct from subcutaneous fat under the skin. High visceral fat is strongly associated with insulin resistance, type 2 diabetes, cardiovascular disease, and metabolic syndrome. Waist circumference above 90cm for men or 80cm for women (WHO Asian guidelines) indicates elevated visceral fat risk.

How do I reduce body fat healthily?

The most evidence-based approach is a modest caloric deficit (300–500 kcal/day below TDEE) combined with resistance training to preserve muscle mass. Crash diets cause muscle loss alongside fat loss, worsening body composition. Studies consistently show that high-protein diets (1.6–2.2g per kg body weight) during a deficit help preserve lean mass while losing fat.

Fitness & Health

Body Fat Calculator

Estimate your body fat percentage using the US Navy Method

Body Fat Calculator

Estimate your body fat percentage using the US Navy Method

Your Measurements

Gender

Unit System

Age

Weight (kg)

Height (cm)

Neck (cm)

Waist (cm)

Your Results

Enter your measurements to calculate body fat percentage

Health Disclaimer: Body fat calculations using measurements are estimates and may not be as accurate as professional methods (DEXA scan, hydrostatic weighing). Results vary based on measurement accuracy and individual factors. Not a substitute for professional medical assessment.

What is the Body Fat Calculator (US Navy Method)?

Body fat percentage is the proportion of your total body weight that is made up of fat mass. It is a more meaningful health metric than BMI because it directly estimates fat versus lean mass (muscle, bone, organs, water). This calculator uses the US Navy Method — a circumference-based estimation formula developed for the United States Navy to screen recruits.

The US Navy Method uses neck and waist circumference (and hip circumference for women) along with height to estimate body fat percentage. It was validated by Hodgdon and Beckett (1984) at the Naval Health Research Center. While less precise than DEXA scans or hydrostatic weighing, it is well-validated for the general population and requires only a measuring tape.

Body fat percentage standards differ significantly by sex and age. Men generally have lower essential fat (2–5%) and healthy ranges (6–24%), while women have higher essential fat (10–13%) due to sex-specific fat (breasts, uterus, hormonal storage) with healthy ranges around 16–30%.

Method

US Navy (circumference)

Men — Essential

2 – 5%

Men — Athletic

6 – 13%

Men — Healthy

14 – 24%

Women — Athletic

14 – 20%

Women — Healthy

21 – 31%

How to Use This Calculator

Formula:Men: %Fat = 86.010 × log₁₀(abdomen − neck) − 70.041 × log₁₀(height) + 36.76 | Women includes hip measurement

Sex: Select male or female — the formula differs significantly between sexes.

Height: Stand straight, measure without shoes in cm or inches.

Neck: Measure below the larynx (Adam's apple), perpendicular to the neck axis.

Waist (Men): Measure at the navel level, not at the narrowest point.

Waist (Women): Measure at the narrowest point of the abdomen.

Hip (Women only): Measure at the widest point of the hips and buttocks.

Body Fat % Classifications (American Council on Exercise)

• Essential fat (men): 2–5% — minimum for organ function
• Essential fat (women): 10–13% — includes sex-specific fat
• Athletes (men): 6–13% — competitive sport range
• Athletes (women): 14–20% — competitive sport range
• Obese (men/women): 25%+ / 32%+ — elevated health risk

Source: Hodgdon & Beckett (1984), Naval Health Research Center; American Council on Exercise (ACE) Body Fat Classifications; WHO Waist Circumference Guidelines for Asian populations

?Frequently Asked Questions

More Fitness Tools

Ideal Weight Calculator

Water Intake Calculator

Sleep Calculator

Stretching Guide

Workout Split Planner