The Body Fat Calculator estimates your body fat percentage from a few simple tape-measure measurements, using the U.S. Navy circumference method. Enter your height, neck, and waist (plus hip for women) and it works out how much of your body weight is fat — a more useful health indicator than weight or BMI alone.
If you also enter your weight, it shows your fat mass and lean (fat-free) mass, and it places you in a fitness category from essential fat to obese. Everything is calculated in your browser and nothing is stored.
How to measure your body fat
- Choose metric (cm) or imperial (inches) and your gender.
- Measure your neck just below the larynx (Adam’s apple), keeping the tape slightly downward at the front.
- Measure your waist horizontally at the navel; women also measure the hips at their widest point.
- Enter the measurements (and optionally your weight) to see your body fat percentage, category, and fat/lean mass.
What is a healthy body fat percentage?
Healthy ranges differ by sex because women naturally carry more essential fat. For men, roughly 6–17% is considered fit and 18–24% average; for women, roughly 14–24% is fit and 25–31% average. Very low body fat is not healthy either — a minimum of essential fat is needed for the body to function.
- Men — Essential: 2–5%, Athletes: 6–13%, Fitness: 14–17%, Average: 18–24%, Obese: 25%+
- Women — Essential: 10–13%, Athletes: 14–20%, Fitness: 21–24%, Average: 25–31%, Obese: 32%+
Body fat vs BMI
BMI uses only height and weight, so it cannot tell fat from muscle — a muscular person can have a high BMI with low body fat. Body fat percentage measures composition directly, giving a clearer picture of fitness. Using both together is more informative than either alone.
Frequently Asked Questions
How accurate is the U.S. Navy body fat method?
For most people it is accurate to within about 3–4% of methods like skinfold calipers, provided you measure carefully. It is an estimate, not a lab measurement — techniques such as DEXA scanning are more precise but require special equipment.
Where exactly do I measure?
Measure the neck just below the larynx, the waist horizontally at the navel, and (for women) the hips at their widest point. Keep the tape snug but not compressing the skin, and measure without holding your breath.
Why do women need to measure their hips?
The Navy formula for women includes the hip measurement because women’s body fat distribution differs from men’s. Men’s formula uses only neck and waist.
What is the difference between fat mass and lean mass?
Fat mass is the weight of body fat you carry; lean mass (or fat-free mass) is everything else — muscle, bone, organs, and water. Entering your weight lets the calculator split it into these two parts.
What is a good body fat percentage?
It depends on your sex and goals. Generally, the “fitness” range (14–17% for men, 21–24% for women) reflects a lean, healthy physique, while athletes are often lower. Extremely low body fat can be unhealthy.