Body Fat Calculator
Estimate your body fat percentage using the US Navy, US Army, or BMI-based method. Free, private, no signup required.
Body Fat Calculator
Estimate your body fat percentage
Most popular circumference method
💡 Tip: Measure waist at navel level (men) or narrowest point (women). Measure neck just below Adam's apple.
How to Use
- 1 Select your gender (male or female) — formulas differ by sex
- 2 Choose a calculation method: US Navy, US Army, or BMI-Based
- 3 Enter your body measurements: height, weight, and tape measurements where required
- 4 For US Navy method: measure your neck, waist, and hip (women only) circumference in cm or inches
- 5 View your estimated body fat percentage, fitness category, fat mass, and lean body mass instantly
What You Get
Three scientifically-validated body fat estimation methods: US Navy circumference method (most accurate tape-based), US Army one-site test (2023 update), and BMI-derived estimate. Real-time calculations with body composition breakdown and category classification.
Input: Male, 180 cm, 85 kg, neck 38 cm, waist 90 cm (Navy)
Output: Body fat: ~19.9% (Average category), Fat mass: 16.9 kg, Lean mass: 68.1 kg
Input: Female, 165 cm, 62 kg, neck 32 cm, waist 72 cm, hip 96 cm (Navy)
Output: Body fat: ~26.7% (Average category), Fat mass: 16.6 kg, Lean mass: 45.4 kg
Input: Male, 175 cm, 80 kg, waist 88 cm (Army)
Output: Body fat: ~20.8% (Average category), Fat mass: 16.6 kg, Lean mass: 63.4 kg
What is a healthy body fat percentage?
Healthy body fat ranges depend on gender. For men, 14-17% is considered "Fitness" and 18-24% is "Average." For women, 21-24% is "Fitness" and 25-31% is "Average." Essential fat (minimum needed for health) is 2-5% for men and 10-13% for women. Athletes typically carry 6-13% (men) or 14-20% (women).
How accurate is the US Navy body fat calculator?
The US Navy circumference method is accurate to within 3-4% of DEXA scan results for most people. It is more accurate than BMI-based estimates because it accounts for body shape through tape measurements of the neck, waist, and hips. For best results, take each measurement three times and use the average.
How do I measure my waist for body fat calculation?
For the US Navy method, men should measure at the navel (belly button) level. Women should measure at the narrowest point of their abdomen, typically just above the navel. Stand relaxed, breathe normally, and do not suck in your stomach. Use a flexible measuring tape held snug but not compressing the skin.
What is the difference between body fat and BMI?
BMI (Body Mass Index) is simply weight divided by height squared — it does not distinguish between fat and muscle. Two people with the same BMI can have very different body fat percentages. A muscular athlete may have a "overweight" BMI but low body fat, while a sedentary person may have a "normal" BMI but high body fat. Body fat percentage is a more accurate indicator of health.
How is the US Army body fat test calculated?
The US Army introduced a simplified one-site tape test in 2023. It uses your body weight and abdominal circumference (measured at navel level). For men: %BF = -26.97 - (0.12 x weight in lbs) + (1.99 x abdomen in inches). For women: %BF = -9.15 - (0.015 x weight in lbs) + (1.27 x abdomen in inches). This replaced the older multi-site tape test.
How can I lower my body fat percentage?
Lowering body fat requires a caloric deficit (eating fewer calories than you burn) combined with strength training to preserve muscle mass. Aim for 0.5-1% body fat loss per month for sustainable results. High protein intake (1.6-2.2g per kg bodyweight), adequate sleep, and progressive resistance training are the most evidence-based approaches. Avoid crash diets, which cause muscle loss.
What is lean body mass?
Lean body mass (LBM) is everything in your body that is not fat: muscles, bones, organs, water, and connective tissue. It is calculated as total weight minus fat mass. For example, if you weigh 80 kg with 20% body fat, your fat mass is 16 kg and your lean body mass is 64 kg. Tracking LBM helps ensure you are losing fat rather than muscle during a diet.
Why do men and women have different body fat ranges?
Women naturally carry more essential body fat than men due to biological functions including hormone production, reproductive health, and breast tissue. Women need a minimum of about 10-13% body fat for basic health, compared to 2-5% for men. This is why healthy and athletic body fat ranges are approximately 8-12 percentage points higher for women.
100% client-side – your measurements never leave your device. All calculations are performed locally in your browser.