💪 Body Fat Calculator

Estimate body fat % using the U.S. Navy circumference method — no calipers needed.

Gender

Units

Height (in)

Neck (in)

Waist (in)

Weight (lb)

Body Fat

17.5%

Fitness

Fat Mass

31.5 lb

14.3 kg

Lean Body Mass

148.5 lb

67.3 kg

📏 How to measure

Neck: Just below the larynx, looking straight ahead.
Waist: At the navel for men, at the narrowest point for women.
Hip (women): At the widest point of the hips/buttocks.

This is the U.S. Navy circumference method. It’s accurate within ~3% for most people.

How This Tool Works

This body fat calculator estimates your body fat percentage using the U.S. Navy circumference method — a field-tested formula developed by the Department of Defense. It requires only a few body measurements (neck, waist, and hip circumference for women; neck and waist for men) plus your height. While not as precise as hydrostatic weighing or DEXA scans, the Navy method provides a practical, equipment-free estimate that correlates well with more expensive methods and is far more informative than BMI alone for assessing body composition.

Formula / Methodology

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

💡 Tips & Best Practices

1Essential fat levels: 2–5% for men, 10–13% for women. Below these ranges is dangerous.
2Athletes typically range 6–13% (men) and 14–20% (women). Fitness range is 14–17% (men) and 21–24% (women).
3Measure at the same time of day (morning is best) for consistent tracking over time.
4Body fat percentage is a better indicator of health and fitness progress than weight alone.

Frequently Asked Questions

How accurate is the Navy body fat method?

The Navy method is accurate within about ±3–4% for most people. It is most accurate for people in the 10–30% body fat range. For highly muscular or very lean individuals, DEXA scans or hydrostatic weighing are more reliable.

What is a healthy body fat percentage?

For men: 10–20% is generally considered healthy, with 14–17% being the "fitness" range. For women: 18–28% is healthy, with 21–24% being the fitness range. Essential fat (needed for organ function) is 2–5% for men and 10–13% for women.