Body fat percentage ranges — American Council on Exercise
What body fat percentage measures
Your body weight consists of two components: fat mass and fat-free mass (also called lean mass). Fat-free mass includes muscle tissue, bone, organs, and water. Body fat percentage expresses fat mass as a fraction of total body weight.
Body fat percentage = (Fat mass / Total body weight) x 100
A person weighing 80 kg with 16 kg of fat mass has a body fat percentage of 16/80 x 100 = 20%. Their lean mass is 80 - 16 = 64 kg.
Body fat percentage is considered more clinically informative than BMI because two people with identical BMI values can have very different body compositions. A 30-year-old male athlete and a sedentary 60-year-old may both have a BMI of 27, but the athlete may have 12% body fat while the sedentary individual has 28%. Their health risk profiles are completely different despite identical BMI values.
Body fat percentage ranges by sex — ACE and WHO classifications
| Classification | Women | Men |
|---|---|---|
| Essential fat | 10 - 13% | 2 - 5% |
| Athletic | 14 - 20% | 6 - 13% |
| Fitness | 21 - 24% | 14 - 17% |
| Acceptable | 25 - 31% | 18 - 24% |
| Obese | 32% + | 25% + |
Method 1: The US Navy circumference formula
Worked examples
For men: BF% = 495 / (1,0324 - 0,19077 x log10(85 - 38) + 0,15456 x log10(180)) - 450. log10(47) = 1,672. log10(180) = 2,255. BF% = 495 / (1,0324 - 0,19077 x 1,672 + 0,15456 x 2,255) - 450 = 495 / (1,0324 - 0,3190 + 0,3485) - 450 = 495 / 1,0619 - 450 = 466,1 - 450 = 16,1%. This falls within the fitness range for men.
Fat mass = 80 x 0,18 = 14,4 kg. Lean mass = 80 - 14,4 = 65,6 kg. This breakdown is useful for setting fitness goals: to reduce body fat to 15%, the person needs to lose fat mass while maintaining lean mass. Target fat mass at 15%: if lean mass stays at 65,6 kg and that represents 85% of body weight, total weight = 65,6 / 0,85 = 77,2 kg. Target fat loss = 80 - 77,2 = 2,8 kg.
Calculate your body fat percentage
Enter your measurements to estimate body fat percentage using the US Navy formula.
Measurement methods and their accuracy
Several methods exist for measuring body fat percentage, with varying accuracy and accessibility.
US Navy formula (tape measure): uses circumference measurements to estimate body fat. Accuracy: within 3 to 4 percentage points. No equipment needed beyond a tape measure. Free and widely available. Best for tracking trends over time rather than establishing an exact baseline.
Skinfold callipers: a trained assessor pinches the skin at specific sites (typically 3 or 7 sites) and measures the thickness of the fat layer. Accuracy: within 3 to 4% when performed correctly. Requires skill and consistent technique. Low cost. The Jackson-Pollock 3-site formula is the most commonly used.
Bioelectrical Impedance Analysis (BIA): passes a small electrical current through the body and measures resistance. Fat conducts electricity poorly; muscle (which contains water) conducts well. Accuracy: within 3 to 5%, highly variable depending on hydration level. Consumer scales and handheld devices use this method.
DEXA scan (Dual-Energy X-ray Absorptiometry): an X-ray based scan that measures bone density, fat mass, and lean mass separately. Accuracy: within 1 to 2%. The most accurate non-invasive method available. Requires a hospital or clinical setting. Cost: approximately 100 to 300 euros per scan.
Hydrostatic weighing: measures body density by comparing weight in air to weight submerged in water. Accuracy: within 1 to 3%. Highly accurate but requires specialised equipment. Rarely available outside research settings.
Body fat percentage vs BMI
BMI and body fat percentage both assess body composition but through different measurements and with different strengths.
BMI requires only weight and height — two measurements anyone can take. It produces a single number with well-established population health correlations. Its limitation is that it cannot distinguish fat mass from lean mass.
Body fat percentage directly measures the ratio of fat to total mass. It is more clinically informative but requires either circumference measurements (Navy formula), callipers, BIA scales, or a DEXA scan.
The two measures often agree but can diverge substantially in specific groups:
Athletes: high muscle mass produces elevated BMI but low body fat. A rugby player with BMI 29 (overweight) may have 14% body fat (athletic range).
Elderły: loss of muscle mass (sarcopenia) can produce normal BMI but elevated body fat. A 70-year-old with BMI 23 (normal) may have 35% body fat (obese range) due to low muscle mass.
Women: naturally carry higher body fat at the same BMI as men due to hormonal and physiological differences. Standard BMI thresholds do not adjust for this.
Common mistakes
Methodology
Body fat percentage ranges follow the American Council on Exercise classification, which is the most widely cited standard in fitness literature. The US Navy formula uses the Hodgdon-Beckett equations (1984). Accuracy estimates for each method are derived from published validation studies comparing each method to hydrostatic weighing as the criterion measure.
Body fat percentage estimates from circumference formulas and BIA are approximations. For clinical decisions, DEXA scan measurement is recommended.
Calculate your body fat percentage now
Enter your measurements to estimate body fat using the US Navy circumference formula.
Frequently asked questions
Formula based on standard mathematical and financial methods. Results are for informational purposes. Last reviewed May 2026. Version 1.