Body Fat Calculator
Estimate your body fat percentage using the U.S. Navy method.
Body Fat Guide
Understanding Body Fat Percentage
Body fat percentage estimates how much of your body is fat compared to everything else (muscle, bone, organs, and water). The U.S. Navy method uses simple tape measurements to provide a practical estimate without special equipment.
While not as precise as DEXA scans, the method is consistent and helpful for tracking changes over time when you measure the same way, under similar conditions.
- What it uses: Height, neck, and waist for men; height, neck, waist, and hips for women.
- When to measure: Ideally in the morning before eating or after using the restroom.
- Best for: Tracking trends over weeks and months rather than one-off precision.
Body Fat Categories
- Men: Essential 2–5%, Athletes 6–13%, Fitness 14–17%, Average 18–24%, Obese 25%+
- Women: Essential 10–13%, Athletes 14–20%, Fitness 21–24%, Average 25–31%, Obese 32%+
- Performance impact: Extremely low levels can harm hormones and recovery; very high levels raise health risks.
Limitations and Considerations
- Measurement error: A 0.5–1 cm difference on waist/neck can shift the result.
- Hydration and timing: Bloating, meals, and time of day can change waist size.
- Body type variation: Distribution of fat and muscle differs across individuals.
- Method assumptions: Navy equations were derived from specific populations.
Actionable Steps
- Measure consistently: Same tape, same posture, same spot each time.
- Track trends: Re-check weekly or biweekly and look for direction over time.
- Pair with weight: Use the optional weight field to estimate fat mass vs lean mass.
- Combine metrics: Track waist size, body weight, and strength performance too.
- Consult a pro: If you have health concerns, speak with a healthcare provider.
Important: This calculator provides an estimate only. Individual results may vary. Do not use body fat results alone to diagnose or treat health conditions.
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