What is Body Fat Percentage?
Body fat percentage is the proportion of your total body weight that consists of fat tissue. It is one of the most informative measures of physical fitness and health, because it distinguishes between fat mass and lean mass (muscle, bone, organs, water). Unlike BMI, which only considers height and weight, body fat percentage tells you how much of your weight is actually fat — making it a far better predictor of metabolic health, athletic performance, and disease risk.
The US Navy circumference method is a widely used field test that estimates body fat from simple body measurements. For men, it uses waist and neck circumference along with height. For women, it adds hip circumference to the formula. While not as precise as DEXA scans or hydrostatic weighing, the Navy method is accurate to within 3–4% for most people and requires only a measuring tape.
How to Use the Body Fat Calculator
- Select your Gender — the formula and category ranges differ between men and women.
- Enter your Height in feet and inches.
- Enter your Weight in pounds.
- Measure and enter your Waist circumference (at the navel for men, narrowest point for women).
- Measure and enter your Neck circumference (just below the larynx).
- Women also enter Hip circumference (at the widest point).
- Results update automatically — see your body fat %, fat mass, lean mass, and health category.
Why Use Our Body Fat Calculator?
- Clinically Validated — Uses the official US Navy method trusted by military fitness programs.
- No Equipment Needed — All you need is a measuring tape.
- Clear Categories — Results are classified from Essential to Obese so you know where you stand.
- Live Results — Updates instantly as you type.
- Privacy First — All calculations run in your browser; no data is ever sent to a server.
Frequently Asked Questions
Body fat percentage is the fraction of your total body weight that is fat tissue, expressed as a percentage. For example, if you weigh 180 lbs and carry 36 lbs of fat, your body fat percentage is 20%. It is widely considered a better health indicator than BMI because it accounts for body composition rather than just total weight relative to height.
Healthy body fat ranges differ by gender. For men, 14–17% is considered fitness level and 18–24% is acceptable. For women, 21–24% is fitness level and 25–31% is acceptable. Athletes typically fall in the 6–13% range for men and 14–20% for women. Essential fat — the minimum needed for survival — is below 6% for men and below 14% for women, and should not be targeted.
The US Navy circumference method has an accuracy of approximately ±3–4% compared to DEXA scans (the gold standard). It is more accurate than BMI but less precise than hydrostatic weighing or DEXA. Measurement technique matters — take measurements to the nearest 0.5 inch, measure at the correct body landmarks, and take 2–3 readings to get a consistent average for best results.
Reducing body fat requires a sustained caloric deficit — consuming fewer calories than you burn. Strength training preserves lean muscle while you lose fat, making your physique leaner at the same body fat percentage. High-protein diets (0.8–1.2g per pound of body weight) support muscle retention. Cardio accelerates the deficit. A realistic rate of fat loss is 0.5–1 lb per week. Avoid crash diets as they tend to burn muscle as well as fat.