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Body Fat Percentage Calculator

Estimate your body fat percentage using the US Navy method.

Last updated: June 13, 2026

Calculator

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Results

Body Fat Percentage11.1%

Category: Athletic

How to Use This Calculator

  1. 1Select your gender.
  2. 2Measure and enter your waist circumference at the navel.
  3. 3Measure and enter your neck circumference.
  4. 4For women, also measure and enter hip circumference. Enter your height in inches.

Formula Explanation

The US Navy method uses body circumference measurements and a logarithmic formula to estimate body fat percentage.

Men: BF% = 495 / (1.0324 − 0.19077×log10(waist−neck) + 0.15456×log10(height)) − 450 Women: BF% = 495 / (1.29579 − 0.35004×log10(waist+hip−neck) + 0.22100×log10(height)) − 450

Variables:

waistWaist circumference in inches at the navel
neckNeck circumference in inches
hipHip circumference (women only)

Worked Examples

Male: 34" waist, 15" neck, 70" height

  1. 1. log10(34-15) = log10(19) = 1.2788
  2. 2. log10(70) = 1.8451
  3. 3. BF% = 495 / (1.0324 - 0.19077(1.2788) + 0.15456(1.8451)) - 450
Result: Body Fat: ~18.5% (Average category)

Female: 30" waist, 13" neck, 38" hips, 65" height

  1. 1. log10(30+38-13) = log10(55) = 1.7404
  2. 2. log10(65) = 1.8129
  3. 3. BF% = 495 / (1.29579 - 0.35004(1.7404) + 0.22100(1.8129)) - 450
Result: Body Fat: ~25.2% (Fit category)

Why Use This Calculator

  • No special equipment needed — just a tape measure.
  • US Navy method is well-validated and widely used in military fitness assessments.
  • More informative than BMI for assessing health risk and fitness progress.
  • Tracks changes over time as you build muscle and lose fat.
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Tips & Best Practices

  • Measure waist at the navel, not where your belt sits.
  • Keep the tape snug but not compressing skin.
  • Measure first thing in the morning for consistency.
  • Take 2–3 measurements and use the average for best accuracy.

Common Mistakes to Avoid

❌ Sucking in your stomach while measuring waist circumference.

✅ Stand relaxed and breathe normally during measurement.

❌ Measuring neck at the wrong spot (too high or too low).

✅ Measure just below the Adam's apple at the narrowest point.

❌ Women forgetting to enter hip measurement, which is required.

✅ Measure hips at the widest point of your buttocks.

Frequently Asked Questions

How accurate is the US Navy body fat method?
The US Navy method is accurate to within 1–3% of underwater weighing (hydrostatic) for most people. It may be less accurate for very lean or very obese individuals.
What is a healthy body fat percentage?
For men, 14–24% is considered healthy. For women, 21–31%. Athletes typically carry 6–13% (men) or 14–20% (women). Essential fat minimums are 2–5% for men and 10–13% for women.
Is body fat percentage better than BMI?
Body fat percentage provides more information because it measures actual fat, while BMI only considers weight relative to height. Two people with the same BMI can have very different body fat levels.
How fast can I reduce body fat?
A safe rate of fat loss is 0.5–1% of body weight per week. This typically means losing 1–2 lbs per week for most people while preserving muscle mass.
Can I measure body fat at home?
Yes. The US Navy tape method (used here), skinfold calipers, and bioelectrical impedance scales all work at home. The tape method is free and requires only a fabric tape measure.
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