Body Fat Calculator
Measure your body fat percentage using the US Navy method — just neck, waist, and hip measurements.
Results are estimates for informational purposes only and do not constitute financial, legal, or medical advice.
Our body fat calculator uses the US Navy circumference method — one of the most accurate non-equipment-based formulas. Simply enter your neck, waist (and hip for women), and height measurements to get your body fat percentage and see which fitness category you fall into.
Body fat percentage is a more useful health metric than weight or BMI alone. Two people with the same weight and height can have very different body composition: one may be lean and muscular while the other carries excess fat. Knowing your body fat percentage helps you set meaningful fitness goals and track real progress.
Frequently Asked Questions
How is body fat percentage calculated?
This calculator uses the US Navy method. For men: 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450. For women, hip measurement is also included. All measurements are in centimetres.
What is a healthy body fat percentage?
For men, 14–20% is considered fitness level and 21–24% acceptable. For women, 21–28% is fitness level and 29–35% acceptable. Essential fat (minimum needed for survival) is around 3–5% for men and 10–13% for women.
Where should I measure waist circumference?
Measure your waist at the narrowest point, usually around the navel level. For the most accurate result, take the measurement in the morning before eating, standing upright with relaxed muscles.
Is the US Navy method accurate?
The US Navy method is accurate to within 3–4% compared to DEXA scans, making it one of the best field methods. It is less accurate for very muscular or very obese individuals. For clinical precision, DEXA or hydrostatic weighing is recommended.
What is the most accurate way to measure body fat?
DEXA (dual-energy X-ray absorptiometry) is considered the gold standard, with accuracy within 1–2%. Hydrostatic (underwater) weighing and Bod Pod (air displacement plethysmography) are also highly accurate. Skinfold callipers measured by a trained professional give around 3% accuracy. The US Navy circumference method (used here) is a practical field estimate with about 3–4% accuracy.
How does high body fat affect my health?
Excess body fat — especially visceral (abdominal) fat — is associated with increased risk of type 2 diabetes, heart disease, high blood pressure, sleep apnea, certain cancers, and metabolic syndrome. Even modest fat loss of 5–10% of body weight significantly reduces these risks. It's not just the amount but the location of fat that matters — abdominal fat is more metabolically active and harmful than subcutaneous fat.
What is visceral fat and why is it dangerous?
Visceral fat is the fat stored deep inside the abdomen, surrounding internal organs like the liver, pancreas, and intestines. Unlike subcutaneous fat (under the skin), visceral fat secretes inflammatory hormones and cytokines that disrupt insulin signalling and promote cardiovascular disease. High waist circumference is the main external indicator of excess visceral fat.
How can I reduce my body fat percentage?
The most effective approach: create a moderate caloric deficit (300–500 kcal/day), eat adequate protein (1.6–2.2 g/kg) to preserve muscle, do regular resistance training 3–4× per week, and include cardio for additional caloric expenditure. Aim to lose 0.5–1% of body weight per week — faster rates increase muscle loss. Sleep of 7–9 hours per night is also critical as sleep deprivation increases cortisol and fat storage.
Does high muscle mass affect the accuracy of this calculator?
Yes. The US Navy circumference method can underestimate body fat in very muscular individuals because large muscle mass can increase neck and waist measurements in ways that don't reflect true fat content. Conversely, it may overestimate fat in individuals with small bone structure. For highly trained athletes, DEXA or skinfold measurements are more reliable.
What is the difference between BMI and body fat percentage?
BMI (Body Mass Index) is calculated from height and weight only — it cannot distinguish between fat and muscle. Body fat percentage directly measures the proportion of fat in your total body mass. Two people with identical BMIs can have very different body fat percentages depending on their muscle mass. Body fat percentage is generally considered a more accurate health indicator than BMI, especially for athletes.