Body Fat Calculator
Estimate your body fat percentage using three proven methods. See your category, gauge position, and full body composition breakdown.
Pinch the skinfold between your thumb and forefinger and measure with calipers. Men: chest, abdomen, thigh. Women: tricep, suprailiac, thigh.
Uses age, sex, height, and weight to estimate body fat from BMI. Simplest method but least accurate for muscular or very lean individuals.
Understanding Body Fat Percentage
Body fat percentage represents the proportion of your total body weight that is fat tissue. Unlike BMI alone, it provides insight into body composition -- distinguishing between fat mass and lean mass (muscle, bones, organs, water).
Calculation Methods
U.S. Navy Method -- Uses circumference measurements (waist, neck, and hip for women) along with height. The Navy method is the most practical tape-based approach, accurate within 1-3% for most body types. It applies the formula:
- Men: 86.010 * log10(waist - neck) - 70.041 * log10(height) + 36.76
- Women: 163.205 * log10(waist + hip - neck) - 97.684 * log10(height) - 78.387
BMI-Based (Deurenberg) -- Estimates body fat from BMI, age, and sex. The simplest method: BF% = 1.20 * BMI + 0.23 * Age - 10.8 * Sex - 5.4 (Sex = 1 for males, 0 for females). Convenient but less accurate for muscular or very lean individuals.
Jackson-Pollock 3-Site Skinfold -- Uses three skinfold caliper measurements. Men: chest, abdomen, thigh. Women: tricep, suprailiac, thigh. Requires calipers but can be very accurate with consistent technique.
Body Fat Ranges by Category
The American Council on Exercise (ACE) classifies body fat into five categories:
- Essential Fat -- Minimum fat needed for basic health. Men: 2-5%. Women: 10-13%.
- Athletes -- Typical for active competitors. Men: 6-13%. Women: 14-20%.
- Fitness -- Healthy and fit appearance. Men: 14-17%. Women: 21-24%.
- Average -- Acceptable but could improve. Men: 18-24%. Women: 25-31%.
- Obese -- Elevated health risk. Men: 25%+. Women: 32%+.
Body Fat Calculator FAQ
How accurate is the Navy body fat method?
The U.S. Navy circumference method estimates body fat within 1-3% of DEXA scans for most people. It uses waist, neck, and hip measurements along with height. It is more accurate than BMI-based estimates because it accounts for body shape rather than just weight and height.
What is a healthy body fat percentage?
For men, 14-17% is considered fitness level and 18-24% is average. For women, 21-24% is fitness level and 25-31% is average. Essential fat minimums are 2-5% for men and 10-13% for women. These ranges vary slightly by age group.
What is the difference between fat mass and lean mass?
Fat mass is the total weight of fat in your body. Lean mass (also called fat-free mass) includes everything else: muscles, bones, organs, water, and connective tissue. Body fat percentage is fat mass divided by total body weight, multiplied by 100.
Which body fat measurement method is best?
DEXA scans and hydrostatic weighing are the gold standard. Among estimation methods, the Navy tape method is most practical and reasonably accurate. BMI-based formulas are the simplest but least accurate. Skinfold calipers require proper technique but can be very accurate with practice.
Why does my BMI-based body fat differ from the Navy method?
BMI only uses height and weight, so it cannot distinguish muscle from fat. The Navy method uses circumference measurements that better reflect actual body shape. Muscular people will typically get higher body fat estimates from BMI than from Navy method.
How should I measure my waist for the Navy method?
Measure your waist at the navel (belly button) level. Stand relaxed, do not suck in your stomach. Wrap a soft tape measure around your waist horizontally. The tape should be snug but not compressing the skin. Measure first thing in the morning for consistency.
Related Tools
- BMI Calculator -- calculate your body mass index
- TDEE Calculator -- estimate daily caloric needs
- Percentage Calculator -- general percentage calculations
Privacy & Limitations
- All calculations run entirely in your browser -- nothing is sent to any server.
- Results are estimates and should not replace professional medical advice.
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Body Fat Calculator FAQ
How accurate is the Navy body fat method?
The U.S. Navy circumference method estimates body fat within 1-3% of DEXA scans for most people. It uses waist, neck, and hip measurements along with height. It is more accurate than BMI-based estimates because it accounts for body shape, not just weight and height.
What is a healthy body fat percentage?
For men, 14-17% is considered fitness level and 18-24% is average. For women, 21-24% is fitness level and 25-31% is average. Essential fat minimums are 2-5% for men and 10-13% for women. These ranges vary slightly by age group.
What is the difference between fat mass and lean mass?
Fat mass is the total weight of fat in your body. Lean mass (also called fat-free mass) includes everything else: muscles, bones, organs, water, and connective tissue. Body fat percentage is fat mass divided by total body weight, multiplied by 100.
Which body fat measurement method is best?
DEXA scans and hydrostatic weighing are the gold standard. Among estimation methods, the Navy tape method is most practical and reasonably accurate. BMI-based formulas are the simplest but least accurate. Skinfold calipers require proper technique but can be very accurate with practice.