Body Fat Calculator
Body fat percentage measures what proportion of your total weight is fat tissue, as opposed to muscle, bone, water, and organs. Unlike BMI, which only considers height and weight, body fat percentage distinguishes between lean mass and fat mass, making it a more accurate health indicator. The Navy method used here estimates body fat from circumference measurements: for men, neck and waist; for women, neck, waist, and hips. These feed into a logarithmic formula developed by the US Navy and validated across large populations. Healthy ranges differ by sex: for adult men, 10–20% is considered fit (21–24% acceptable); for women, 18–28% is fit (29–31% acceptable). In Australia, body fat tracking is used in ADF fitness assessments, personal training programs, and pre-season sporting screenings. Results update live as you type.
Frequently Asked Questions
What is body fat percentage?
Body fat percentage is the proportion of your total body weight that consists of adipose tissue (fat). It includes essential fat, which your body needs for basic physiological functions (around 3-5% for men and 8-12% for women), and storage fat, which accumulates under your skin and around organs. Unlike BMI, body fat percentage directly measures your actual fat mass relative to lean tissue, giving a more accurate picture of your body composition.
What are healthy body fat ranges?
For men: 10-20% is considered fitness level, 20-25% is average, and 25%+ is above average. For women: 18-28% is fitness level, 28-32% is average, and 32%+ is above average. These ranges are approximate and can overlap with athletic performance ranges depending on the sport. Athletes in endurance sports typically sit at the lower end of these ranges.
How do I measure body fat accurately?
DEXA (dual-energy X-ray absorptiometry) scans and hydrostatic weighing are considered the most accurate methods, with error rates around 2-3%. Skinfold calipers used by an experienced practitioner can achieve 3-5% error. Bioelectrical impedance analysis (scales and handheld devices) is convenient but accuracy varies significantly based on hydration levels, with errors of 3-8%.
Where do you lose fat from first?
Fat loss occurs systemically across your entire body, not from specific areas you target. Genetics determine your unique pattern of fat distribution, meaning some people lose fat from their belly first while others lose from limbs first. Spot-reduction (exercising specific body parts to lose fat there) has been debunked by research. Consistent calorie deficit through diet and exercise is the only proven way to reduce overall body fat.
What is visceral fat vs subcutaneous fat?
Visceral fat (also called intra-abdominal fat) wraps around your internal organs in the abdominal cavity and is strongly associated with metabolic health risks including cardiovascular disease and type 2 diabetes. Subcutaneous fat sits directly under your skin throughout your body. While subcutaneous fat is less metabolically harmful, excess visceral fat is particularly dangerous because it releases fatty acids and inflammatory compounds directly into your bloodstream via the portal vein.
What body fat percentage do athletes have?
Elite athletes vary considerably by sport: endurance athletes typically range 5-12% for men and 12-20% for women; strength and power athletes usually sit at 5-12% for men; team sports athletes commonly fall between 10-18%. Extremely low body fat percentages are generally not sustainable long-term and can compromise immune function and hormonal balance, particularly for women who need higher essential fat levels for reproductive health.
What is lean body mass and why does it matter?
Lean body mass (LBM) is everything in your body that isn't fat, including muscles, bones, organs, water, and connective tissue. Knowing your LBM helps you set realistic goals when building muscle or losing fat. LBM decreases with age (muscle loss), which is why strength training becomes increasingly important. When you lose weight, tracking whether you're losing fat vs. LBM helps determine if your diet and exercise plan is working.
Why do different body fat formulas give different results?
Different body fat estimation methods use different inputs and assumptions. The US Navy method relies on circumference measurements and assumes certain body proportions. The BMI-based formula uses body mass index, which doesn't distinguish between muscle and fat. Both have ~3-5% error margins. Large discrepancies between methods often occur in very muscular individuals or those with unusual body compositions. If methods agree within 3%, your estimate is more reliable.