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Body Fat Calculator

Estimate your body fat percentage using the US Navy method with neck, waist, and hip measurements.

Estimate body fat percentage using the US Navy circumference method — measure neck, waist, and hips (women) with a tape measure for a field-ready estimate without calipers or DEXA scans.

Body fat percentage tells you more about composition than scale weight alone. Two people at the same weight can have very different fat and muscle ratios — this metric matters for athletes, dieters, and health screening.

Accuracy depends on consistent measurement technique: measure at the same time of day, tape parallel to the floor, and do not pull the tape tight. Results are estimates — ±3–4% vs. professional methods is normal.

Links to BMI and ideal weight tools for context. Not for children under 18 or pregnant women without medical guidance.

Formula

Men: 86.010×log₁₀(waist − neck) − 70.041×log₁₀(height) + 36.76 · Women: add hip measurement term

Common Uses

  • ✓Track fat loss during a cut
  • ✓Fitness assessment beyond BMI
  • ✓Military and sports screening prep
  • ✓Compare progress month over month
  • ✓Set body composition goals with a trainer

How to Use the Body Fat Calculator

  1. 1

    Enter your measurements

    Measure and input your neck, waist, and hip (women only) circumferences.

  2. 2

    Enter height and gender

    Provide your height and select your gender.

  3. 3

    View body fat result

    See your estimated body fat percentage and fitness category.

💡 Tips & Tricks

  • •Measure circumferences in the morning before eating for consistency.
  • •Use a flexible tape measure and measure at the same location each time.
  • •Track changes over time rather than focusing on a single measurement.

Frequently Asked Questions

How is body fat percentage calculated?
This calculator uses the US Navy method, which uses neck, waist, and hip (for women) circumference measurements along with height to estimate body fat percentage.
What is a healthy body fat percentage?
For men, 10–20% is considered fit to average. For women, 18–28% is considered fit to average. Athletes typically have lower percentages.
Is the US Navy method accurate?
The US Navy method is reasonably accurate (within 3–4%) for most people and is widely used as a practical field measurement. DEXA scans are the gold standard for accuracy.
What is the difference between body fat % and BMI?
BMI uses only weight and height and does not distinguish between fat and muscle. Body fat percentage directly measures the proportion of fat in your body.

Related Calculators

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Ideal Weight

Healthy weight range by height

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