Body Fat Calculator
Calculate your body fat percentage using the US Navy method. Get fat mass, lean mass, and your fitness category — no equipment needed.
Your Measurements
Body Fat
16.9%
Fitness
Fat Mass
12.7 kg
Lean Mass
62.3 kg
Male body fat categories
How It Works
The US Navy circumference method estimates body fat using body measurements rather than skinfold calipers or DEXA scans. For men, it uses waist and neck circumference with height. For women, it adds hip circumference. The formula is validated against hydrostatic weighing and gives results within 3–4% accuracy for most people.
US Navy Formula
Men: %BF = 495 / (1.0324 − 0.19077×log10(waist−neck) + 0.15456×log10(height)) − 450. Women: %BF = 495 / (1.29579 − 0.35004×log10(waist+hip−neck) + 0.22100×log10(height)) − 450
Body Fat Categories
- Essential Fat
- Men <6% / Women <14% — minimum for basic body functions
- Athlete
- Men 6–13% / Women 14–20% — competitive athletic range
- Fitness
- Men 14–17% / Women 21–24% — lean and healthy
- Acceptable
- Men 18–24% / Women 25–31% — average range
- Obese
- Men ≥25% / Women ≥32% — elevated health risk
Frequently Asked Questions
What is a healthy body fat percentage?
For men: Essential fat 2–5%, Athletes 6–13%, Fitness 14–17%, Acceptable 18–24%, Obese 25%+. For women: Essential fat 10–13%, Athletes 14–20%, Fitness 21–24%, Acceptable 25–31%, Obese 32%+. Athletes have lower body fat but higher lean mass.
How accurate is the Navy method?
The US Navy method is accurate within 3–4% compared to DEXA scans for most people. It tends to underestimate body fat in very lean individuals and overestimate in very obese individuals. For best results, measure in the morning before eating.
Where exactly should I measure waist circumference?
For men: measure at the level of the navel (belly button). For women: measure at the narrowest point of the waist, typically just above the navel. Keep the tape horizontal and don't suck in your stomach.
What is lean body mass?
Lean body mass is everything in your body except fat — muscles, bones, organs, water, and connective tissue. It is the metabolically active tissue that burns calories even at rest. Higher lean mass means a higher resting metabolic rate.