Body Fat Calculator
Stand straight against a wall, no shoes.
Around the neck, below the Adam's apple.
At the navel, relaxed — don't suck in.
| Navy method | – |
| BMI method (cross-check) | – |
| Body fat mass | – |
| Lean body mass | – |
ACE body-fat categories
Try other calculators
Find your daily calories for fat loss or muscle gain.
Check your Body Mass Index in seconds.
Turn your calories into protein, carb and fat targets.
How the body fat calculator works
This calculator uses the U.S. Navy circumference method — the same tape-measure formula the American military has used since the 1980s. It estimates body fat from your neck, waist (and hip) measurements plus height, and lands within about 3–4% of expensive DEXA scans for most people.
Because no single formula is perfect, we also show the BMI-based estimate (Deurenberg formula) as a cross-check, plus your fat mass and lean mass in kg or lbs, and where you sit on the ACE fitness category scale.
How to measure correctly
Use a soft tape, measure in the morning, and don't pull tight: neck just below the Adam's apple, waist at the navel while relaxed (don't suck in), hips at the widest point. Small errors here move the result more than any formula choice.
Frequently asked questions
How accurate is the U.S. Navy body fat method?
Within about 3–4% of DEXA scans for most healthy adults — good enough to track trends. Tape placement matters more than the formula: measure the waist at the navel, relaxed, and the neck just below the Adam's apple.
Why do women need a hip measurement?
The Navy formula for women uses waist + hip − neck because fat distributes differently. For men, waist − neck is enough. Skipping the hip measurement for women makes the result unreliable.
What is a healthy body fat percentage?
For men, 14–24% is typical (athletes 6–13%); for women, 21–31% (athletes 14–20%). Essential fat — the minimum for basic health — is about 2–5% for men and 10–13% for women.
Why does the BMI method give a different number?
The BMI method estimates fat from height, weight and age alone, so it can't tell muscle from fat. The Navy tape method measures your actual shape, which is why we show it as the main result and BMI as a cross-check.