Enter your age, gender, height, neck, waist, and hip measurements to calculate your estimated body fat percentage, fat mass, and lean body mass instantly using the US Navy body composition algorithm.
How to use this calculator
Select your unit system (metric or imperial) and biological sex.
Enter your age, height, and body weight.
Measure your neck circumference just below the larynx (adam's apple).
Measure your waist circumference horizontally at the navel level for men or narrowest point for women.
For women, measure hip circumference at the widest point.
Read your body fat percentage, fat mass, lean mass, and ACE body fat category.
Measurements in cm. Fat Mass = Weight × (BF% ÷ 100). Lean Mass = Weight − Fat Mass.
Example
Male 175cm height, 75kg weight, 38cm neck, 85cm waist → Body Fat ≈ 18.2% (Average range, 13.6 kg fat mass, 61.4 kg lean mass).
Key insights
The US Navy body fat method estimates body composition within 3–4% accuracy compared to DEXA scans.
Body fat percentage is a better indicator of fitness and health risks than BMI alone because it distinguishes muscle from fat.
Essential body fat is approximately 2–5% for men and 10–13% for women, necessary for nerve function and hormone regulation.
Fat mass can be reduced through a calorie deficit and cardiovascular exercise, while resistance training preserves lean body mass.
Fluctuations in body water content can cause minor day-to-day changes in tape measurements; measure consistently under similar conditions.
How to interpret your result
Body Fat Categories (ACE Standards)
For men: Athletes (6-13%), Fitness (14-17%), Average (18-24%), Obese (25%+). For women: Athletes (14-20%), Fitness (21-24%), Average (25-31%), Obese (32%+).
Lean Body Mass vs. Fat Mass
Lean body mass includes muscle tissue, bones, organs, and body water. Maintaining or increasing lean mass raises resting metabolic rate.
Measurement Consistency
Take tape measurements in the morning before eating or working out, keeping the tape snug against skin without compressing soft tissue.
Frequently asked questions
How accurate is the US Navy body fat method?
The Navy method is typically accurate to within 3–4% of DEXA body composition scans, making it one of the best accessible non-clinical methods.
Why do women require higher body fat percentages than men?
Women require higher essential body fat (10-13% vs 2-5%) for reproductive health, hormone regulation, and tissue structure.
How often should I measure my body fat?
Measuring every 2 to 4 weeks provides a clear trend while smoothing out day-to-day water weight fluctuations.
Related calculators
BMI Calculator — Compute your Body Mass Index and see where you stand, in metric or imperial units.
Calorie Calculator — Estimate your daily calorie needs (BMR & TDEE) for maintenance, loss or gain.