Body Fat Percentage Calculator - US Navy Method (Tape Measure)

💪 Enter Your Measurements

Inches Centimeters

Height

Neck

Waist

Hip

0.0%

Body Fat Categories

US Navy Body Fat Formula

Men

%BF = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76

(All measurements in inches)

Women

%BF = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387

(All measurements in inches)

Why It Works

This method, developed by the US Navy for fitness assessment, relies on the correlation between circumference measurements and body fat percentage. It's not as precise as DEXA scans or hydrostatic weighing, but requires no special equipment and is accurate enough for tracking changes over time.

Frequently Asked Questions

The US Navy circumference method is generally accurate within about 3-4% of body fat compared to more precise methods like DEXA scans or hydrostatic weighing, for most people. It works reasonably well for the general population but can be less accurate for very muscular individuals or those with unusual body fat distribution. It's a convenient, equipment-free estimate rather than a clinical-grade measurement.

For men, essential fat is 2-5%, athletes typically range 6-13%, fitness enthusiasts 14-17%, average 18-24%, and obese is 25%+. For women, essential fat is 10-13%, athletes 14-20%, fitness 21-24%, average 25-31%, and obese is 32%+. Women naturally carry more essential body fat than men due to reproductive and hormonal functions.

BMI only uses height and weight, so it cannot distinguish between muscle and fat. Body fat percentage directly estimates the proportion of your body that is fat versus lean mass (muscle, bone, organs, water). Two people can have the identical BMI but very different body fat percentages depending on muscle mass - which is why body fat percentage is often considered a more meaningful health indicator for individuals, especially athletes.

Measure your neck just below the larynx (Adam's apple), with the tape sloping slightly downward to the front. Measure your waist at its narrowest point, usually just above the belly button, without sucking in your stomach. For hips (women only), measure around the widest part of the buttocks. Keep the tape snug but not compressing the skin, and take each measurement 2-3 times to average out small errors.

Body Fat Percentage Calculator - US Navy Tape Measure Method

Body fat percentage tells you what portion of your body weight is fat versus lean mass (muscle, bone, organs, and water) - a more direct health indicator than BMI, which cannot distinguish fat from muscle. The US Navy method estimates body fat using simple circumference measurements (neck, waist, and hip for women), making it accessible with nothing more than a tape measure.

What you need: A flexible tape measure, your height, and neck/waist measurements (plus hip if female)
Accuracy: Typically within 3-4% of body fat compared to DEXA scans, for most people

Body Fat Categories at a Glance

These are the American Council on Exercise (ACE) categories, commonly used as a reference point:

Essential Fat: Men 2-5%, Women 10-13% - the minimum needed for basic physiological function
Athletes: Men 6-13%, Women 14-20% - typical for competitive athletes
Fitness: Men 14-17%, Women 21-24% - lean and visibly fit
Average: Men 18-24%, Women 25-31% - typical for the general population
Obese: Men 25%+, Women 32%+ - associated with increased health risk

Getting Accurate Measurements

Measurement technique matters more than most people expect for this method, since small errors in circumference measurements get amplified by the formula. Measure your neck just below the larynx, sloping slightly downward at the front. Measure your waist at its narrowest point without sucking in your stomach - this is usually just above the navel, not at the navel itself. For women, measure hips at the widest point of the buttocks. Take each measurement two or three times and use the average for the most reliable result.

How this calculator works, and where the numbers come from

The Body Fat Calculator applies the standard formula for this calculation to the values you enter and updates the result as you type. The calculation itself happens in your browser, and the page explains the method so you can check any result by hand.

Please note: This tool gives general estimates based on published population formulas. It is not medical advice and does not replace assessment by a doctor, dietitian or other qualified professional.

Sources and further reading

Learn more

Read our guide: What BMI Tells You, and What It Quietly Misses

Last reviewed: October 6, 2026 by the CalcQube Editorial Team. See our editorial policy for how we build and check calculators, or report an error.

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