Body Fat Calculator
Body fat percentage is the share of your weight that comes from fat. This calculator uses the U.S. Navy body fat formula and your measurements (waist, neck, height, and hip for women) to estimate your body fat %, fat mass, and lean body mass. No photos, AI, or image analysis — formula-based only. Results are hidden until you run the calculation.
What Is the Body Fat Calculator?
The body fat calculator estimates your body fat percentage from simple measurements using the U.S. Navy formula. You enter waist, neck, and height (and hip for women); no photos or AI. It returns body fat %, fat mass, and lean body mass in kg and lbs, plus a category (e.g. fitness, average). Body fat percentage reflects composition better than weight or BMI alone.
How Does the Body Fat Calculator Work?
The calculator uses the U.S. Navy body fat formula: for men, waist, neck, and height in cm are plugged into a standard equation; for women, hip is added. All measurements are converted to metric first. The formula outputs body fat %; fat mass is then weight × (body fat % ÷ 100), and lean mass is weight minus fat mass.
Why Use This Body Fat Calculator?
Tracking body fat percentage helps you see whether you are losing fat or muscle and set realistic goals. This body fat calculator works at home with a tape measure — no DEXA or calipers required. Use it with our calorie calculator and calorie deficit calculator to plan intake while losing fat.
Who Should Use This Tool?
Anyone who wants an estimate of body fat percentage from measurements can use this body fat calculator. It suits people tracking fat loss, athletes monitoring composition, and anyone curious about body fat without access to DEXA or other methods. For context, pair with our BMI calculator or ideal body weight calculator.
What Is Body Fat Percentage?
Body fat percentage is the proportion of your total body weight that is fat mass, as opposed to lean mass (muscle, bone, water, organs). Unlike BMI, which only uses height and weight, body fat % better reflects body composition. Two people can have the same BMI but very different body fat levels.
How to Calculate Body Fat
You can estimate body fat at home using measurement-based formulas (like the U.S. Navy method), skinfold calipers, or smart scales. This calculator uses the Navy formula: you enter waist, neck, and height in metric or imperial; women also enter hip. All values are converted to metric (cm, kg) and plugged into the formula. You get body fat %, then fat mass = weight × (body fat % / 100) and lean body mass = weight − fat mass. No photos or AI required.
U.S. Navy Method Explained
The U.S. Navy body fat formula was developed to estimate body fat from a few circumference measurements. For men it uses waist, neck, and height (all in cm). For women it uses waist, hip, neck, and height. The formula is based on regression equations that relate these measurements to body density and then to body fat percentage. It is one of the most widely used “body fat by measurements” methods and works well for general population ranges. Measure waist at the navel, neck below the larynx, and hip at the widest part for consistent results.
Is the Navy Method Accurate?
The Navy method is a reasonable estimate for most people when measurements are taken consistently. It can be off by a few percentage points compared to DEXA or underwater weighing, and accuracy varies with body type and how you measure. Use it for tracking trends over time (same formula, same technique) rather than an absolute “true” number. For context on weight and height, pair with our BMI calculator or ideal body weight calculator.
Healthy Body Fat Ranges
Healthy body fat ranges differ by sex. For men, essential fat is about 2–5%, athletes often 6–13%, fitness 14–17%, average 18–24%, and obese 25%+. For women, essential is about 10–13%, athletes 14–20%, fitness 21–24%, average 25–31%, and obese 32%+. The calculator shows which category your result falls into. These ranges are guidelines; individual goals depend on health, sport, and preference. Use the result to inform nutrition and training — for example with our TDEE calculator and macro calculator.
How to Reduce Body Fat
To reduce body fat, most people need a modest calorie deficit (eating slightly less than they burn), enough protein to preserve muscle, and resistance training. Use our calorie deficit calculator and calorie calculator to set a target intake, and the protein calculator to hit a daily protein goal. Re-measure with this body fat calculator every few weeks to track progress; body fat % and lean body mass are more informative than scale weight alone.