Body Fat Calculator
Estimate your body fat percentage using the U.S. Navy method. Enter your measurements below to get body fat %, lean mass, BMR, TDEE, and macro targets.
Waist: measure at the navel. Neck: measure below the Adam's apple.
Enter your measurements above to see your results.
How the Navy Method Works
The U.S. Navy body fat estimation formula was developed for military fitness assessments. It uses circumference measurements (waist, neck, and hip for women) along with height to estimate body fat percentage. The formula works by correlating body circumferences with body density, which relates to fat vs lean tissue.
For men, the formula focuses on the waist-to-neck ratio relative to height. For women, it adds hip circumference because women naturally store more fat in the lower body. The calculation uses logarithmic math to account for the non-linear relationship between circumferences and body fat.
How Accurate Is This Calculator?
The Navy method has an error margin of +/- 3-5% for most people. It is less accurate than clinical methods like DEXA scans (+/- 1-2%) but more accessible since it only requires a tape measure. The main limitations:
- •Overestimates body fat for muscular individuals with larger waists.
- •Cannot distinguish between visceral and subcutaneous fat.
- •Measurement technique affects results. Small differences in tape placement change the output.
For a more accurate estimate without clinic visits, FitCommit uses AI computer vision to analyze body photos and estimate body fat percentage. See how methods compare in our measurement methods comparison.
For the broader method behind FitCommit's body-weight interpretation, read the body weight methodology. It explains how BMI, ideal-weight formulas, body fat percentage, waist measurements, and lean mass fit together.
ACE Body Fat Categories
The American Council on Exercise (ACE) classifies body fat into five categories. These ranges differ between men and women because women have higher essential fat requirements.
| Category | Men | Women |
|---|---|---|
| Essential Fat | 2-5% | 10-13% |
| Athletes | 6-13% | 14-20% |
| Fitness | 14-17% | 21-24% |
| Average | 18-24% | 25-31% |
| Obese | 25-100% | 32-100% |
See what each body fat level looks like in our visual body fat guide with 130 reference images for men and women.
Reviewed by Andrew Menechian, Head of Fitness, FitCommit
Andrew reviews FitCommit's calorie, macro, and body-composition methodology. His background includes 12+ years in fitness, PN1, PNC 1&2, Poliquin PICP 1&2, bodybuilding, powerlifting, and coaching education.
Frequently Asked Questions
How accurate is the Navy method body fat calculator?
The Navy method has an error margin of +/- 3-5% for most people. It works best for average body compositions. It tends to overestimate body fat for muscular individuals and underestimate for those with visceral fat. For higher accuracy, try FitCommit AI body scan (+/- 3-5% with visual analysis) or a clinical DEXA scan (+/- 1-2%).
How do I measure my waist for the body fat calculator?
Measure your waist at the navel (belly button) level. Stand relaxed, do not suck in your stomach. Wrap the tape measure snugly but not tight. Measure at the end of a normal exhale. For consistent results, measure at the same time of day.
Where do I measure my neck for body fat calculation?
Measure your neck just below the larynx (Adam's apple). Keep the tape level and snug. Look straight ahead, not up or down. This measurement is used in both the male and female Navy method formulas.
Why does the calculator need hip measurement for women?
The Navy method uses different formulas for men and women. Women naturally carry more fat around the hips and thighs, so hip circumference improves accuracy. Measure at the widest point of your hips/buttocks while standing with feet together.
What is a healthy body fat percentage?
The American Council on Exercise (ACE) defines healthy ranges as 14-24% for men and 21-31% for women. Athletes may be lower (6-13% men, 14-20% women). Essential fat minimums are 2-5% for men and 10-13% for women. Below essential fat levels is dangerous.
Related Resources
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