How accurate is the US Navy method?

Most research puts the US Navy method within ±3–4 percentage points compared to DEXA scanning for most people. It's less accurate for very lean individuals (below 10% for men, below 18% for women) and for people with unusual fat distribution patterns. For tracking changes over time with consistent measurement technique, it's quite reliable. For an absolute number to use clinically, DEXA or hydrostatic weighing is more precise.

How do I measure correctly?

Neck: measure just below the larynx (Adam's apple), perpendicular to the neck. Waist: measure at the navel for the US Navy method, keeping the tape level and parallel to the floor. Hip (women): measure at the widest point of the hips and buttocks. All measurements should be taken standing, relaxed, first thing in the morning before eating if you want the most consistent results. Measure three times and use the average to reduce error.

What body fat percentage should I aim for?

The fitness category — roughly 14–17% for men and 21–24% for women — is associated with good health, visible muscle definition, and metabolic benefits. Athletic range (6–13% for men, 14–20% for women) is achievable with dedicated training but not required for health. Essential fat (below 5% men, below 13% women) is not a goal — it's a floor below which normal physiological function is impaired. Most non-athlete adults do well targeting the fitness or low end of average range.

Why is body fat percentage better than BMI?

BMI doesn't distinguish between fat and muscle. A muscular 6-foot athlete weighing 225 lbs has a BMI of 30.5, which is classified as obese — but may be 10% body fat. Conversely, a sedentary person at a 'normal' BMI of 22 might be 28% body fat. Body fat percentage directly measures what you're trying to change. BMI is a useful population-level screening tool but a poor individual health metric.

❤️Health

Body Fat Calculator

What is your body fat percentage?

What This Does

Body fat percentage is a more meaningful health metric than weight or BMI alone. Two people can weigh the same and have the same BMI but have drastically different body compositions — one might be 18% body fat, the other 32%. This calculator estimates your body fat percentage without calipers, a DEXA scan, or gym equipment. It uses the US Navy circumference method, developed by Hodgdon and Beckett and validated across large military populations. The method requires only a tape measure: waist circumference, neck circumference, and — for women — hip circumference. These three measurements feed into a logarithmic formula that estimates fat distribution with reasonable accuracy for most adults. Results are shown alongside your lean body mass and fat mass in pounds or kilograms, and categorized against the American Council on Exercise ranges: essential fat, athletic, fitness, average, and obese. These categories are sex-specific because women carry more essential fat for hormonal and reproductive functions — a body fat percentage that would be "athletic" for a man is "essential fat" territory for a woman. The US Navy method is less precise than DEXA scanning or hydrostatic weighing, but it's within 3–4% for most people and far more accessible. Use it as a baseline and track trends over time rather than treating a single measurement as definitive.

When Should You Use This?

→Establishing a body composition baseline at the start of a fitness program
→Tracking progress when the scale isn't moving but body composition may be changing
→Understanding whether your BMI reflects actual fat or muscle mass
→Setting a body fat goal more specific than a goal weight
→Comparing your current composition to fitness category benchmarks

Example Scenario

Marcus is 185 lbs and frustrated that the scale hasn't moved in 3 weeks despite consistent training. He measures his neck (16 inches), waist (36 inches), and height (71 inches). The calculator estimates 22.4% body fat — 185 × 22.4% = 41.4 lbs of fat mass, 143.6 lbs of lean mass. He remeasures 6 weeks later: weight is still 184 lbs, but waist is now 34.5 inches. New estimate: 19.8% body fat — 36.4 lbs fat, 147.6 lbs lean. He gained 4 lbs of muscle and lost 5 lbs of fat. The scale didn't show it. Body fat percentage did.

💪Body Fat Calculator

Body Fat % & Composition Analyzer

US Navy circumference method. Enter your measurements for instant body fat %, lean mass, fat mass, category, and reduction targets. Results update live.

Weight (lbs)

Height (in)

Neck (in)

Just below the larynx (Adam's apple)

Waist (in)

At navel level, breathe normally

Tip: Measure in the morning before eating, using a non-stretchable tape. Average 2–3 readings per site. Breathe normally — do not suck in.