How accurate is the US Navy body fat formula?

The US Navy method has an accuracy within ±3-4% of more precise methods like DEXA scans for most people. It's less accurate for athletes with unusual muscle distribution.

What is a healthy body fat percentage?

For men, essential fat is 2–5%, athletes 6–13%, fitness 14–17%, acceptable 18–24%, and obese 25%+. For women, essential fat is 10–13%, athletes 14–20%, fitness 21–24%, acceptable 25–31%, and obese 32%+.

Body Fat Calculator (US Navy Method)

Q: Where do I measure waist circumference?

For men, measure at the navel (belly button). For women, measure at the narrowest point of the abdomen, usually about an inch above the navel.

Measurements

Height

Neck circumference

Measure below the larynx

Waist circumference

At navel (men) / narrowest (women)

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% Body Fat

Essential Athlete Fitness Acceptable Obese

Lean body mass

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Fat mass

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Body Fat Categories

Category	Men	Women

Frequently Asked Questions

The US Navy method estimates body fat percentage from circumference measurements (neck, waist, and hips for women) plus height. It uses a logarithmic formula validated by the US Navy and is widely used in military fitness assessments.

The US Navy method has an accuracy within ±3–4% of more precise methods like DEXA scans for most people. It is less accurate for athletes with unusual muscle distribution or those at body fat extremes.

For men, measure at the navel (belly button) with the abdomen relaxed. For women, measure at the narrowest point of the abdomen, usually about an inch above the navel. Do not suck in or push out the stomach.

For men: essential fat 2–5%, athlete 6–13%, fitness 14–17%, acceptable 18–24%, obese 25%+. For women: essential fat 10–13%, athlete 14–20%, fitness 21–24%, acceptable 25–31%, obese 32%+. These ranges are guidelines, not strict medical criteria.

Body Fat Calculator — Overview

The Body Fat Calculator estimates your body fat percentage using the US Navy circumference method, which has been validated as a practical field measurement technique. Unlike BMI, which only looks at weight relative to height, body fat percentage directly distinguishes between lean mass (muscle, bone, water) and adipose tissue (fat). To calculate it, you measure your neck, waist, and — for women — hip circumferences, then enter those values along with your height and sex. The Navy formula uses the logarithm of these measurements to estimate the fat percentage, providing a result that correlates well with more expensive methods like DEXA scans for most individuals. Knowing your body fat percentage is valuable for setting realistic fitness goals, monitoring progress during body recomposition, and understanding cardiovascular risk factors beyond what BMI reveals.

Common Use Cases

Tracking body composition changes during a fitness or diet program

Setting a target body fat percentage for athletic performance goals

Supplementing BMI data with a more body-composition-aware metric

Screening for health risks associated with high body fat levels

How to Use This Tool

Select your sex, then enter your height and the circumference measurements for your neck, waist, and (if female) hips using a flexible tape measure. Measure at the narrowest point for waist and the widest point for hips. The estimated body fat percentage and fitness category appear instantly.

Body Fat Calculator