Body Fat Percentage Calculator: Estimate Your Body Composition
Calculate your body fat percentage using the U.S. Navy method. Just measure your neck, waist, and height — no expensive calipers or DEXA scans required.
What Is Body Fat Percentage?
Your body fat percentage (BFP) is the proportion of your total weight that comes from fat tissue. Unlike BMI, which only considers height and weight, body fat percentage accounts for your actual body composition — distinguishing between fat mass and lean mass (muscle, bone, organs, water).
Knowing your BFP is more useful than knowing your weight alone. Two people at the same weight can have vastly different health profiles depending on their muscle-to-fat ratio.
How Does the U.S. Navy Method Work?
The U.S. Navy body fat formula was developed by the Naval Health Research Center and is used by the U.S. military for fitness assessments. It estimates body fat using circumference measurements:
- Men: Neck and waist measurements + height
- Women: Neck, waist, and hip measurements + height
While not as precise as DEXA scans or hydrostatic weighing, the Navy method correlates within 3–4% of clinical methods — making it the most accurate no-equipment option available.
Body Fat Categories for Men & Women
The American Council on Exercise (ACE) defines these ranges:
- Essential fat: 2–5% (men), 10–13% (women) — minimum for survival
- Athletes: 6–13% (men), 14–20% (women) — visible muscle definition
- Fitness: 14–17% (men), 21–24% (women) — healthy, active lifestyle
- Average: 18–24% (men), 25–31% (women) — acceptable but not optimal
- Obese: 25%+ (men), 32%+ (women) — elevated health risk
Frequently Asked Questions
The Navy method correlates within 3–4% of DEXA scans for most people. It tends to slightly overestimate body fat in very lean individuals and underestimate in those with high abdominal fat. For tracking changes over time, it is highly reliable.
Women naturally store more fat in the hips and thighs (gluteofemoral region) due to estrogen. The Navy formula accounts for this sex-specific fat distribution pattern. Men tend to store fat centrally (abdomen), so waist measurement alone captures most variance.
Healthy ranges increase slightly with age. For men: 20–29 years (10–20%), 30–39 (14–21%), 40–49 (17–24%), 50+ (19–26%). For women: 20–29 years (18–28%), 30–39 (20–30%), 40–49 (23–33%), 50+ (25–35%).
Neck and waist measurements are easiest with a partner, but you can do them yourself using a mirror. Keep the tape parallel to the floor, snug but not compressing skin. Measure at the same time of day (morning, before eating) for consistency.
Combine a moderate calorie deficit (300–500 calories below maintenance) with resistance training 3–4 times per week. Prioritize protein (1.6–2.2g per kg bodyweight), sleep 7–9 hours, and manage stress. Aim to lose 0.5–1% body fat per week.