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Body Fat Percentage Calculator

Estimate your body fat percentage using the US Navy circumference method. Enter your measurements to see your body fat %, fitness category, lean mass, and fat mass.

Disclaimer: This calculator provides an estimate only and is not a substitute for professional medical assessment. Consult a healthcare provider for accurate body composition analysis.
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Measure at navel level

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Measure just below the larynx

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Total height in inches

Enter your measurements, then click Calculate to estimate your body fat percentage.

How Body Fat Estimation Works

The US Navy Method

The US Navy body fat estimation method, developed by Hodgdon and Beckett at the Naval Health Research Center, uses simple circumference measurements to estimate body fat percentage without expensive equipment. It was adopted by the US military as a standardized fitness assessment tool and has since become one of the most widely used field methods for estimating body composition.

How the Formula Works

For men, the formula uses waist and neck circumferences along with height. It calculates body fat percentage as: 86.010 times the log of the difference between waist and neck circumference, minus 70.041 times the log of height, plus a constant of 36.76. For women, hip circumference is also included: 163.205 times the log of the sum of waist and hip minus neck circumference, minus 97.684 times the log of height, minus 78.387.

The logarithmic approach accounts for the non-linear relationship between body circumference and fat distribution. The waist measurement captures abdominal fat, which is the most metabolically significant fat depot. The neck measurement serves as a proxy for upper-body lean mass, and the hip measurement for women accounts for gender-specific fat storage patterns.

Interpreting Your Results

Your body fat percentage is categorized into fitness levels ranging from essential fat through obese. The calculator also shows your lean body mass (everything except fat, including muscle, bone, organs, and water) and your total fat mass in pounds. Use these numbers as a baseline and track changes over time rather than focusing on a single reading. For the most accurate trends, measure under consistent conditions — same time of day, same measuring points, and same tape tension.

Frequently asked questions

Body fat percentage is the proportion of your total body weight that is composed of fat tissue. It includes both essential fat (needed for basic physiological functions like hormone regulation and organ protection) and storage fat (excess energy reserves). Unlike BMI, body fat percentage distinguishes between fat and lean mass, making it a more accurate indicator of body composition and overall health.

Healthy body fat ranges differ by gender. For men, essential fat is 2–5%, athletes typically range from 6–13%, fitness-oriented individuals fall between 14–17%, and average is 18–24%. For women, essential fat is 10–13%, athletes range from 14–20%, fitness is 21–24%, and average is 25–31%. Body fat above 25% for men or 32% for women is generally classified as obese. These ranges account for the fact that women naturally carry more essential fat.

The US Navy circumference method has been validated against hydrostatic weighing and typically falls within 1–3% of more expensive laboratory methods like DEXA scans. It is considered one of the most reliable field methods because it uses multiple body measurements to account for individual variation in fat distribution. For best accuracy, measure at the same time of day, use a flexible tape measure pulled snug but not compressing the skin, and take each measurement two or three times to average out any inconsistency.

Reducing body fat requires a sustained calorie deficit combined with resistance training to preserve lean muscle mass. Aim for a moderate deficit of 300–500 calories per day, prioritize protein intake (0.7–1.0 g per pound of body weight), and include strength training at least two to three times per week. Cardiovascular exercise, adequate sleep, and stress management also play important roles. Avoid crash diets, as rapid weight loss often leads to muscle loss and metabolic adaptation.

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