Estimate your body fat percentage using the U.S. Navy method based on your body measurements.
Measure to the nearest 0.5 cm (1/4 inch). For men, measure waist at navel. For women, measure waist at smallest width and hips at widest point.
A body fat percentage calculator answers the question that BMI alone can’t: “Of my total body weight, how much is fat — and how much is muscle, bone, and everything else?”
BMI tells you if your weight is appropriate for your height. Body fat percentage tells you about your composition. Two people can have the same BMI but radically different body fat levels — one might be muscular and lean, the other overfat but under‑muscled. Body fat percentage cuts through that confusion.
Unlike BMI (which uses only height and weight), body fat percentage requires additional measurements: skinfold thickness (with calipers), circumference measurements (neck, waist, hips), or sometimes bioelectrical impedance (scale). The most accessible method for home use is the U.S. Navy Method, which uses circumference measurements and height. It’s not as accurate as a DEXA scan, but it’s far better than guessing.
The 2026 Reality: With the rise of “body recomposition” (losing fat and gaining muscle simultaneously), more people are tracking body fat percentage rather than scale weight. The scale might not move while you lose fat and gain muscle — but your body fat percentage will drop. A body fat calculator helps you see progress that the scale hides.
Men: %BF = 86.010 × log10(waist – neck) – 70.041 × log10(height) + 36.76
Women: %BF = 163.205 × log10(waist + hip – neck) – 97.684 × log10(height) – 78.387
Example (Man):
Neck 15", Waist 33", Height 70" → 15.6% body fat
Pro Tip: Take each measurement three times and average them. For consistency, measure at the same time of day (morning, before eating or drinking) and under the same conditions.
| Category | Body Fat % |
|---|---|
| Essential fat | 2‑5% |
| Athletes | 6‑13% |
| Fitness | 14‑17% |
| Acceptable | 18‑24% |
| Overfat / Obese | 25%+ |
| Category | Body Fat % |
|---|---|
| Essential fat | 10‑13% |
| Athletes | 14‑20% |
| Fitness | 21‑24% |
| Acceptable | 25‑31% |
| Overfat / Obese | 32%+ |
* Sources: American Council on Exercise (ACE), National Institutes of Health
| Method | Accuracy | Accessibility | Best For |
|---|---|---|---|
| DEXA scan | ±1‑2% | Clinical setting | Gold standard |
| BIA scale | ±3‑5% | Home | Convenience |
| U.S. Navy | ±3‑5% | Home (Tape) | Free & Repeatable |
| Caliper | ±3‑5% | Home/Gym | Tracking trends |
Lower isn’t always better. Essential fat ranges exist for a reason. For men, below 6‑8% can cause hormone issues. For women, below 14‑16% can disrupt menstrual cycles.
| Population | Men | Women |
|---|---|---|
| Competitive Bodybuilder | 3‑6% | 8‑12% |
| Endurance Athlete | 6‑12% | 14‑20% |
| Team Sport Athlete | 8‑15% | 16‑22% |
Focus on trends over weeks and months, not daily changes. Water, food, and technique cause small fluctuations.
"If weight is stable but body fat % is dropping, you're gaining muscle while losing fat — the ideal 'body recomposition'."
Pro Tip: Take progress photos. They often show changes before the numbers do.
Formula: Waist (inches) ÷ Height (inches)
Keep your waist circumference to less than half your height. This threshold (below 0.5) is a powerful predictor of visceral fat and metabolic disease risk for both men and women.
Inconsistent technique: Measuring at different times or angles will skew trends.
Tape tension: Pulling the tape too tight or too loose changes measurements by 1-2%.
Method switching: Don't compare DEXA results with Navy method results. Pick one.
Ignoring waist: Waist circumference alone is a stronger risk marker than body fat %.
"Bottom Line: Use the trend, not the exact number. Consistent monthly measurement is the key to seeing real progress."
* This calculator is for informational purposes only. Consult a healthcare professional for medical advice.
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